Extract part of EngineControl::backend_changed into EngineControl::update_midi_options
[ardour.git] / gtk2_ardour / engine_dialog.cc
index f0ac059a74abdffc438c899f2ec51c38ed78de98..28e0adcdca97155c5bd2eca768a56c74d3d08842 100644 (file)
 
 #include <boost/scoped_ptr.hpp>
 
-#include <glibmm.h>
 #include <gtkmm/messagedialog.h>
 
 #include "pbd/error.h"
 #include "pbd/xml++.h"
+#include "pbd/unwind.h"
+#include "pbd/failed_constructor.h"
 
+#include <gtkmm/alignment.h>
 #include <gtkmm/stock.h>
 #include <gtkmm/notebook.h>
 #include <gtkmm2ext/utils.h>
 
 #include "ardour/audio_backend.h"
 #include "ardour/audioengine.h"
+#include "ardour/mtdm.h"
+#include "ardour/mididm.h"
 #include "ardour/rc_configuration.h"
+#include "ardour/types.h"
+#include "ardour/profile.h"
 
 #include "pbd/convert.h"
 #include "pbd/error.h"
 
+#include "opts.h"
+#include "debug.h"
+#include "ardour_ui.h"
 #include "engine_dialog.h"
+#include "gui_thread.h"
+#include "utils.h"
 #include "i18n.h"
 
 using namespace std;
@@ -50,576 +61,2011 @@ using namespace Gtk;
 using namespace Gtkmm2ext;
 using namespace PBD;
 using namespace Glib;
+using namespace ARDOUR_UI_UTILS;
+
+#define DEBUG_ECONTROL(msg) DEBUG_TRACE (PBD::DEBUG::EngineControl, string_compose ("%1: %2\n", __LINE__, msg));
+
+static const unsigned int midi_tab = 2;
+static const unsigned int latency_tab = 1; /* zero-based, page zero is the main setup page */
+
+static const char* results_markup = X_("<span weight=\"bold\" size=\"larger\">%1</span>");
 
 EngineControl::EngineControl ()
-       : input_latency_adjustment (0, 0, 99999, 1)
+       : ArdourDialog (_("Audio/MIDI Setup"))
+       , engine_status ("")
+       , basic_packer (9, 4)
+       , input_latency_adjustment (0, 0, 99999, 1)
        , input_latency (input_latency_adjustment)
        , output_latency_adjustment (0, 0, 99999, 1)
        , output_latency (output_latency_adjustment)
-       , input_channels_adjustment (2, 0, 256, 1)
+       , input_channels_adjustment (0, 0, 256, 1)
        , input_channels (input_channels_adjustment)
-       , output_channels_adjustment (2, 0, 256, 1)
+       , output_channels_adjustment (0, 0, 256, 1)
        , output_channels (output_channels_adjustment)
        , ports_adjustment (128, 8, 1024, 1, 16)
        , ports_spinner (ports_adjustment)
-       , realtime_button (_("Realtime"))
-#ifdef __APPLE___
-       , basic_packer (6, 2)
-#else
-       , basic_packer (9, 2)
-#endif
+       , control_app_button (_("Device Control Panel"))
+       , midi_devices_button (_("Midi Device Setup"))
+       , lm_measure_label (_("Measure"))
+       , lm_use_button (_("Use results"))
+       , lm_back_button (_("Back to settings ... (ignore results)"))
+       , lm_button_audio (_("Calibrate Audio"))
+       , lm_table (12, 3)
+       , have_lm_results (false)
+       , lm_running (false)
+       , midi_back_button (_("Back to settings"))
+       , ignore_changes (0)
+       , _desired_sample_rate (0)
+       , started_at_least_once (false)
+       , queue_device_changed (false)
+       , block_signals(0)
 {
        using namespace Notebook_Helpers;
+       vector<string> backend_names;
        Label* label;
-       vector<string> strings;
-       int row = 0;
+       AttachOptions xopt = AttachOptions (FILL|EXPAND);
+       int row;
 
-       _used = false;
+       set_name (X_("AudioMIDISetup"));
 
-       /* basic parameters */
+       /* the backend combo is the one thing that is ALWAYS visible */
 
-       basic_packer.set_spacings (6);
+       vector<const ARDOUR::AudioBackendInfo*> backends = ARDOUR::AudioEngine::instance()->available_backends();
 
-       strings.clear ();
+       if (backends.empty()) {
+               MessageDialog msg (string_compose (_("No audio/MIDI backends detected. %1 cannot run\n\n(This is a build/packaging/system error. It should never happen.)"), PROGRAM_NAME));
+               msg.run ();
+               throw failed_constructor ();
+       }
 
-       vector<const ARDOUR::AudioBackendInfo*> backends = ARDOUR::AudioEngine::instance()->available_backends();
        for (vector<const ARDOUR::AudioBackendInfo*>::const_iterator b = backends.begin(); b != backends.end(); ++b) {
-               strings.push_back ((*b)->name);
+               backend_names.push_back ((*b)->name);
        }
 
-       set_popdown_strings (backend_combo, strings);
-       backend_combo.set_active_text (strings.front());
+       set_popdown_strings (backend_combo, backend_names);
 
-       backend_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::backend_changed));
-       backend_changed ();
+       /* setup basic packing characteristics for the table used on the main
+        * tab of the notebook
+        */
 
-       driver_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::driver_changed));
+       basic_packer.set_spacings (6);
+       basic_packer.set_border_width (12);
+       basic_packer.set_homogeneous (false);
 
-       strings.clear ();
-       strings.push_back (_("None"));
-#ifdef __APPLE__
-       strings.push_back (_("coremidi"));
-#else
-       strings.push_back (_("seq"));
-       strings.push_back (_("raw"));
-#endif
-       set_popdown_strings (midi_driver_combo, strings);
-       midi_driver_combo.set_active_text (strings.front ());
+       /* pack it in */
+
+       basic_hbox.pack_start (basic_packer, false, false);
+
+       /* latency measurement tab */
+
+       lm_title.set_markup (string_compose ("<span size=\"large\" weight=\"bold\">%1</span>", _("Latency Measurement Tool")));
 
        row = 0;
+       lm_table.set_row_spacings (12);
+       lm_table.set_col_spacings (6);
+       lm_table.set_homogeneous (false);
 
-       label = manage (left_aligned_label (_("Audio System:")));
-       basic_packer.attach (*label, 0, 1, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
-       basic_packer.attach (backend_combo, 1, 2, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
+       lm_table.attach (lm_title, 0, 3, row, row+1, xopt, (AttachOptions) 0);
        row++;
 
-       label = manage (left_aligned_label (_("Driver:")));
-       basic_packer.attach (*label, 0, 1, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
-       basic_packer.attach (driver_combo, 1, 2, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
-       row++;
+       lm_preamble.set_width_chars (60);
+       lm_preamble.set_line_wrap (true);
+       lm_preamble.set_markup (_("<span weight=\"bold\">Turn down the volume on your audio equipment to a very low level.</span>"));
 
-       label = manage (left_aligned_label (_("Device:")));
-       basic_packer.attach (*label, 0, 1, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
-       basic_packer.attach (interface_combo, 1, 2, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
+       lm_table.attach (lm_preamble, 0, 3, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
        row++;
 
-       label = manage (left_aligned_label (_("Sample rate:")));
-       basic_packer.attach (*label, 0, 1, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
-       basic_packer.attach (sample_rate_combo, 1, 2, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
-       row++;
+       Gtk::Label* preamble;
+       preamble = manage (new Label);
+       preamble->set_width_chars (60);
+       preamble->set_line_wrap (true);
+       preamble->set_markup (_("Select two channels below and connect them using a cable."));
 
-       label = manage (left_aligned_label (_("Buffer size:")));
-       basic_packer.attach (*label, 0, 1, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
-       basic_packer.attach (buffer_size_combo, 1, 2, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
+       lm_table.attach (*preamble, 0, 3, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
        row++;
 
-       label = manage (left_aligned_label (_("Hardware input latency:")));
-       basic_packer.attach (*label, 0, 1, row, row+1, FILL|EXPAND, (AttachOptions) 0);
-       basic_packer.attach (input_latency, 1, 2, row, row+1, FILL|EXPAND, (AttachOptions) 0);
-       label = manage (left_aligned_label (_("samples")));
-       basic_packer.attach (*label, 2, 3, row, row+1, FILL|EXPAND, (AttachOptions) 0);
+       label = manage (new Label (_("Output channel")));
+       lm_table.attach (*label, 0, 1, row, row+1, xopt, (AttachOptions) 0);
+
+       Gtk::Alignment* misc_align = manage (new Alignment (0.0, 0.5));
+       misc_align->add (lm_output_channel_combo);
+       lm_table.attach (*misc_align, 1, 3, row, row+1, xopt, (AttachOptions) 0);
        ++row;
 
-       label = manage (left_aligned_label (_("Hardware output latency:")));
-       basic_packer.attach (*label, 0, 1, row, row+1, FILL|EXPAND, (AttachOptions) 0);
-       basic_packer.attach (output_latency, 1, 2, row, row+1, FILL|EXPAND, (AttachOptions) 0);
-       label = manage (left_aligned_label (_("samples")));
-       basic_packer.attach (*label, 2, 3, row, row+1, FILL|EXPAND, (AttachOptions) 0);
+       label = manage (new Label (_("Input channel")));
+       lm_table.attach (*label, 0, 1, row, row+1, xopt, (AttachOptions) 0);
+
+       misc_align = manage (new Alignment (0.0, 0.5));
+       misc_align->add (lm_input_channel_combo);
+       lm_table.attach (*misc_align, 1, 3, row, row+1, FILL, (AttachOptions) 0);
        ++row;
 
-       sr_connection = sample_rate_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::reshow_buffer_sizes));
+       lm_measure_label.set_padding (10, 10);
+       lm_measure_button.add (lm_measure_label);
+       lm_measure_button.signal_clicked().connect (sigc::mem_fun (*this, &EngineControl::latency_button_clicked));
+       lm_use_button.signal_clicked().connect (sigc::mem_fun (*this, &EngineControl::use_latency_button_clicked));
+       lm_back_button_signal = lm_back_button.signal_clicked().connect (sigc::bind (sigc::mem_fun (notebook, &Gtk::Notebook::set_current_page), 0));
+
+       lm_use_button.set_sensitive (false);
 
-       interface_combo.set_size_request (250, -1);
-       input_device_combo.set_size_request (250, -1);
-       output_device_combo.set_size_request (250, -1);
+       /* Increase the default spacing around the labels of these three
+        * buttons
+        */
 
-       interface_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::interface_changed));
+       Gtk::Misc* l;
 
-       basic_hbox.pack_start (basic_packer, false, false);
+       if ((l = dynamic_cast<Gtk::Misc*>(lm_use_button.get_child())) != 0) {
+               l->set_padding (10, 10);
+       }
 
-       basic_packer.set_border_width (12);
-       midi_packer.set_border_width (12);
+       if ((l = dynamic_cast<Gtk::Misc*>(lm_back_button.get_child())) != 0) {
+               l->set_padding (10, 10);
+       }
+
+       preamble = manage (new Label);
+       preamble->set_width_chars (60);
+       preamble->set_line_wrap (true);
+       preamble->set_markup (_("Once the channels are connected, click the \"Measure\" button."));
+       lm_table.attach (*preamble, 0, 3, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
+       row++;
+
+       preamble = manage (new Label);
+       preamble->set_width_chars (60);
+       preamble->set_line_wrap (true);
+       preamble->set_markup (_("When satisfied with the results, click the \"Use results\" button."));
+       lm_table.attach (*preamble, 0, 3, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
+
+       ++row; // skip a row in the table
+       ++row; // skip a row in the table
+
+       lm_table.attach (lm_results, 0, 3, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
+
+       ++row; // skip a row in the table
+       ++row; // skip a row in the table
+
+       lm_table.attach (lm_measure_button, 0, 1, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
+       lm_table.attach (lm_use_button, 1, 2, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
+       lm_table.attach (lm_back_button, 2, 3, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
+
+       lm_results.set_markup (string_compose (results_markup, _("No measurement results yet")));
+
+       lm_vbox.set_border_width (12);
+       lm_vbox.pack_start (lm_table, false, false);
+
+       midi_back_button.signal_clicked().connect (sigc::bind (sigc::mem_fun (notebook, &Gtk::Notebook::set_current_page), 0));
+
+       /* pack it all up */
 
-       notebook.pages().push_back (TabElem (basic_hbox, _("Audio System Settings")));
-       notebook.pages().push_back (TabElem (midi_hbox, _("MIDI Settings")));
+       notebook.pages().push_back (TabElem (basic_vbox, _("Audio")));
+       notebook.pages().push_back (TabElem (lm_vbox, _("Latency")));
+       notebook.pages().push_back (TabElem (midi_vbox, _("MIDI")));
        notebook.set_border_width (12);
 
-       notebook.set_tab_pos (POS_RIGHT);
+       notebook.set_show_tabs (false);
        notebook.show_all ();
 
        notebook.set_name ("SettingsNotebook");
 
-       set_border_width (12);
-       pack_start (notebook);
+       /* packup the notebook */
+
+       get_vbox()->set_border_width (12);
+       get_vbox()->pack_start (notebook);
+
+       get_action_area()->pack_start (engine_status);
+       engine_status.show();
+
+       /* need a special function to print "all available channels" when the
+        * channel counts hit zero.
+        */
+
+       input_channels.signal_output().connect (sigc::bind (sigc::ptr_fun (&EngineControl::print_channel_count), &input_channels));
+       output_channels.signal_output().connect (sigc::bind (sigc::ptr_fun (&EngineControl::print_channel_count), &output_channels));
+
+       midi_devices_button.signal_clicked.connect (mem_fun (*this, &EngineControl::configure_midi_devices));
+       midi_devices_button.set_sensitive (false);
+       midi_devices_button.set_name ("generic button");
+       midi_devices_button.set_can_focus(true);
+
+       control_app_button.signal_clicked().connect (mem_fun (*this, &EngineControl::control_app_button_clicked));
+       manage_control_app_sensitivity ();
+
+       cancel_button = add_button (Gtk::Stock::CLOSE, Gtk::RESPONSE_CANCEL);
+       apply_button = add_button (Gtk::Stock::APPLY, Gtk::RESPONSE_APPLY);
+       ok_button = add_button (Gtk::Stock::OK, Gtk::RESPONSE_OK);
 
        /* Pick up any existing audio setup configuration, if appropriate */
 
-       XMLNode* audio_setup = ARDOUR::Config->extra_xml ("AudioSetup");
-       
+       XMLNode* audio_setup = ARDOUR::Config->extra_xml ("AudioMIDISetup");
+
+       ARDOUR::AudioEngine::instance()->Running.connect (running_connection, MISSING_INVALIDATOR, boost::bind (&EngineControl::engine_running, this), gui_context());
+       ARDOUR::AudioEngine::instance()->Stopped.connect (stopped_connection, MISSING_INVALIDATOR, boost::bind (&EngineControl::engine_stopped, this), gui_context());
+       ARDOUR::AudioEngine::instance()->Halted.connect (stopped_connection, MISSING_INVALIDATOR, boost::bind (&EngineControl::engine_stopped, this), gui_context());
+       ARDOUR::AudioEngine::instance()->DeviceListChanged.connect (devicelist_connection, MISSING_INVALIDATOR, boost::bind (&EngineControl::device_list_changed, this), gui_context());
+
        if (audio_setup) {
                set_state (*audio_setup);
        }
+
+       if (backend_combo.get_active_text().empty()) {
+               PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+               backend_combo.set_active_text (backend_names.front());
+       }
+
+       backend_changed ();
+
+       /* in case the setting the backend failed, e.g. stale config, from set_state(), try again */
+       if (0 == ARDOUR::AudioEngine::instance()->current_backend()) {
+               backend_combo.set_active_text (backend_names.back());
+               /* ignore: don't save state */
+               PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+               backend_changed ();
+       }
+
+       connect_changed_signals ();
+
+       notebook.signal_switch_page().connect (sigc::mem_fun (*this, &EngineControl::on_switch_page));
+
+       connect_disconnect_button.signal_clicked().connect (sigc::mem_fun (*this, &EngineControl::connect_disconnect_click));
+       connect_disconnect_button.set_no_show_all();
+
 }
 
-EngineControl::~EngineControl ()
+void
+EngineControl::connect_changed_signals ()
 {
+       backend_combo_connection = backend_combo.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::backend_changed));
+       driver_combo_connection = driver_combo.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::driver_changed));
+       sample_rate_combo_connection = sample_rate_combo.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::sample_rate_changed));
+       buffer_size_combo_connection = buffer_size_combo.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::buffer_size_changed));
+       device_combo_connection = device_combo.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::device_changed));
+       midi_option_combo_connection = midi_option_combo.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::midi_option_changed));
+
+       input_device_combo_connection = input_device_combo.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::input_device_changed));
+       output_device_combo_connection = output_device_combo.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::output_device_changed));
+
+       input_latency_connection = input_latency.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::parameter_changed));
+       output_latency_connection = output_latency.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::parameter_changed));
+       input_channels_connection = input_channels.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::parameter_changed));
+       output_channels_connection = output_channels.signal_changed ().connect (
+           sigc::mem_fun (*this, &EngineControl::parameter_changed));
+}
 
+void
+EngineControl::block_changed_signals ()
+{
+       if (block_signals++ == 0) {
+               DEBUG_ECONTROL ("Blocking changed signals");
+               backend_combo_connection.block ();
+               driver_combo_connection.block ();
+               sample_rate_combo_connection.block ();
+               buffer_size_combo_connection.block ();
+               device_combo_connection.block ();
+               input_device_combo_connection.block ();
+               output_device_combo_connection.block ();
+               midi_option_combo_connection.block ();
+               input_latency_connection.block ();
+               output_latency_connection.block ();
+               input_channels_connection.block ();
+               output_channels_connection.block ();
+       }
 }
 
 void
-EngineControl::backend_changed ()
+EngineControl::unblock_changed_signals ()
 {
-       string backend_name = backend_combo.get_active_text();
-       boost::shared_ptr<ARDOUR::AudioBackend> backend;
+       if (--block_signals == 0) {
+               DEBUG_ECONTROL ("Unblocking changed signals");
+               backend_combo_connection.unblock ();
+               driver_combo_connection.unblock ();
+               sample_rate_combo_connection.unblock ();
+               buffer_size_combo_connection.unblock ();
+               device_combo_connection.unblock ();
+               input_device_combo_connection.unblock ();
+               output_device_combo_connection.unblock ();
+               midi_option_combo_connection.unblock ();
+               input_latency_connection.unblock ();
+               output_latency_connection.unblock ();
+               input_channels_connection.unblock ();
+               output_channels_connection.unblock ();
+       }
+}
 
-       if (!(backend = ARDOUR::AudioEngine::instance()->set_backend (backend_name, "ardour", ""))) {
-               /* eh? */
-               return;
+EngineControl::SignalBlocker::SignalBlocker (EngineControl& engine_control,
+                                             const std::string& reason)
+    : ec (engine_control)
+    , m_reason (reason)
+{
+       DEBUG_ECONTROL (string_compose ("SignalBlocker: %1", m_reason));
+       ec.block_changed_signals ();
+}
+
+EngineControl::SignalBlocker::~SignalBlocker ()
+{
+       DEBUG_ECONTROL (string_compose ("~SignalBlocker: %1", m_reason));
+       ec.unblock_changed_signals ();
+}
+
+void
+EngineControl::on_show ()
+{
+       ArdourDialog::on_show ();
+       if (!ARDOUR::AudioEngine::instance()->current_backend() || !ARDOUR::AudioEngine::instance()->running()) {
+               // re-check _have_control (jackd running) see #6041
+               backend_changed ();
        }
+       device_changed ();
+       ok_button->grab_focus();
+}
 
-       if (backend->requires_driver_selection()) {
-               vector<string> drivers = backend->enumerate_drivers();
-               driver_combo.set_sensitive (true);
-               set_popdown_strings (driver_combo, drivers);
-               driver_combo.set_active_text (drivers.front());
-               driver_changed ();
-       } else {
-               driver_combo.set_sensitive (false);
-               list_devices ();
+void
+EngineControl::on_response (int response_id)
+{
+       ArdourDialog::on_response (response_id);
+
+       switch (response_id) {
+               case RESPONSE_APPLY:
+                       push_state_to_backend (true);
+                       break;
+               case RESPONSE_OK:
+#ifdef PLATFORM_WINDOWS
+                       // For some reason we don't understand, 'hide()'
+                       // needs to get called first in Windows
+                       hide ();
+
+                       // But if there's no session open, this can produce
+                       // a long gap when nothing appears to be happening.
+                       // Let's show the splash image while we're waiting.
+                       if ( !ARDOUR_COMMAND_LINE::no_splash ) {
+                               if ( ARDOUR_UI::instance() ) {
+                                       if ( !ARDOUR_UI::instance()->session_loaded ) {
+                                               ARDOUR_UI::instance()->show_splash();
+                                       }
+                               }
+                       }
+                       push_state_to_backend (true);
+                       break;
+#else
+                       push_state_to_backend (true);
+                       hide ();
+                       break;
+#endif
+               case RESPONSE_DELETE_EVENT:
+                       {
+                               GdkEventButton ev;
+                               ev.type = GDK_BUTTON_PRESS;
+                               ev.button = 1;
+                               on_delete_event ((GdkEventAny*) &ev);
+                               break;
+                       }
+               default:
+                       hide ();
        }
 }
 
 void
-EngineControl::list_devices ()
+EngineControl::build_notebook ()
 {
-       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
-       assert (backend);
+       Label* label;
+       AttachOptions xopt = AttachOptions (FILL|EXPAND);
 
-       /* now fill out devices, mark sample rates, buffer sizes insensitive */
-           
-       vector<ARDOUR::AudioBackend::DeviceStatus> all_devices = backend->enumerate_devices ();
-       
-       /* NOTE: Ardour currently does not display the "available" field of the
-        * returned devices.
-        *
-        * Doing so would require a different GUI widget than the combo
-        * box/popdown that we currently use, since it has no way to list
-        * items that are not selectable. Something more like a popup menu,
-        * which could have unselectable items, would be appropriate.
-        */
+       /* clear the table */
 
-       vector<string> available_devices;
+       Gtkmm2ext::container_clear (basic_vbox);
+       Gtkmm2ext::container_clear (basic_packer);
 
-       for (vector<ARDOUR::AudioBackend::DeviceStatus>::const_iterator i = all_devices.begin(); i != all_devices.end(); ++i) {
-               available_devices.push_back (i->name);
+       if (control_app_button.get_parent()) {
+               control_app_button.get_parent()->remove (control_app_button);
        }
 
-       set_popdown_strings (interface_combo, available_devices);
-       set_popdown_strings (input_device_combo, available_devices);
-       set_popdown_strings (output_device_combo, available_devices);
-       
-       if (!available_devices.empty()) {
-               interface_combo.set_active_text (available_devices.front());
-               input_device_combo.set_active_text (available_devices.front());
-               output_device_combo.set_active_text (available_devices.front());
+       label = manage (left_aligned_label (_("Audio System:")));
+       basic_packer.attach (*label, 0, 1, 0, 1, xopt, (AttachOptions) 0);
+       basic_packer.attach (backend_combo, 1, 2, 0, 1, xopt, (AttachOptions) 0);
+
+       lm_button_audio.signal_clicked.connect (sigc::mem_fun (*this, &EngineControl::calibrate_audio_latency));
+       lm_button_audio.set_name ("generic button");
+       lm_button_audio.set_can_focus(true);
+
+       if (_have_control) {
+               build_full_control_notebook ();
+       } else {
+               build_no_control_notebook ();
        }
 
-       interface_changed ();
-}
-       
-void
-EngineControl::driver_changed ()
-{
-       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
-       assert (backend);
+       basic_vbox.pack_start (basic_hbox, false, false);
 
-       backend->set_driver (driver_combo.get_active_text());
-       list_devices ();
+       {
+               PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+               basic_vbox.show_all ();
+       }
 }
 
 void
-EngineControl::interface_changed ()
+EngineControl::build_full_control_notebook ()
 {
        boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
        assert (backend);
-       string device_name = interface_combo.get_active_text ();
-       vector<string> s;
 
-       /* don't allow programmatic change to sample_rate_combo to cause a
-          recursive call to this method.
-       */
-          
-       sr_connection.block ();
+       using namespace Notebook_Helpers;
+       Label* label;
+       vector<string> strings;
+       AttachOptions xopt = AttachOptions (FILL|EXPAND);
+       int row = 1; // row zero == backend combo
 
-       /* sample rates */
+       /* start packing it up */
 
-       vector<float> sr = backend->available_sample_rates (device_name);
-       for (vector<float>::const_iterator x = sr.begin(); x != sr.end(); ++x) {
-               char buf[32];
-               if (fmod (*x, 1000.0f)) {
-                       snprintf (buf, sizeof (buf), "%.1f kHz", (*x)/1000.0);
-               } else {
-                       snprintf (buf, sizeof (buf), "%.0f kHz", (*x)/1000.0);
-               }
-               s.push_back (buf);
+       if (backend->requires_driver_selection()) {
+               label = manage (left_aligned_label (_("Driver:")));
+               basic_packer.attach (*label, 0, 1, row, row + 1, xopt, (AttachOptions) 0);
+               basic_packer.attach (driver_combo, 1, 2, row, row + 1, xopt, (AttachOptions) 0);
+               row++;
+       }
+
+       if (backend->use_separate_input_and_output_devices()) {
+               label = manage (left_aligned_label (_("Input Device:")));
+               basic_packer.attach (*label, 0, 1, row, row + 1, xopt, (AttachOptions) 0);
+               basic_packer.attach (input_device_combo, 1, 2, row, row + 1, xopt, (AttachOptions) 0);
+               row++;
+               label = manage (left_aligned_label (_("Output Device:")));
+               basic_packer.attach (*label, 0, 1, row, row + 1, xopt, (AttachOptions) 0);
+               basic_packer.attach (output_device_combo, 1, 2, row, row + 1, xopt, (AttachOptions) 0);
+               row++;
+               // reset so it isn't used in state comparisons
+               device_combo.set_active_text ("");
+       } else {
+               label = manage (left_aligned_label (_("Device:")));
+               basic_packer.attach (*label, 0, 1, row, row + 1, xopt, (AttachOptions) 0);
+               basic_packer.attach (device_combo, 1, 2, row, row + 1, xopt, (AttachOptions) 0);
+               row++;
+               // reset these so they don't get used in state comparisons
+               input_device_combo.set_active_text ("");
+               output_device_combo.set_active_text ("");
        }
 
-       set_popdown_strings (sample_rate_combo, s);
-       sample_rate_combo.set_active_text (s.front());
+       label = manage (left_aligned_label (_("Sample rate:")));
+       basic_packer.attach (*label, 0, 1, row, row + 1, xopt, (AttachOptions) 0);
+       basic_packer.attach (sample_rate_combo, 1, 2, row, row + 1, xopt, (AttachOptions) 0);
+       row++;
+
+
+       label = manage (left_aligned_label (_("Buffer size:")));
+       basic_packer.attach (*label, 0, 1, row, row + 1, xopt, (AttachOptions) 0);
+       basic_packer.attach (buffer_size_combo, 1, 2, row, row + 1, xopt, (AttachOptions) 0);
+       buffer_size_duration_label.set_alignment (0.0); /* left-align */
+       basic_packer.attach (buffer_size_duration_label, 2, 3, row, row+1, SHRINK, (AttachOptions) 0);
+
+       /* button spans 2 rows */
 
-       reshow_buffer_sizes ();
+       basic_packer.attach (control_app_button, 3, 4, row-1, row+1, xopt, xopt);
+       row++;
+
+       input_channels.set_name ("InputChannels");
+       input_channels.set_flags (Gtk::CAN_FOCUS);
+       input_channels.set_digits (0);
+       input_channels.set_wrap (false);
+       output_channels.set_editable (true);
+
+       if (!ARDOUR::Profile->get_mixbus()) {
+               label = manage (left_aligned_label (_("Input Channels:")));
+               basic_packer.attach (*label, 0, 1, row, row+1, xopt, (AttachOptions) 0);
+               basic_packer.attach (input_channels, 1, 2, row, row+1, xopt, (AttachOptions) 0);
+               ++row;
+       }
+       
+       output_channels.set_name ("OutputChannels");
+       output_channels.set_flags (Gtk::CAN_FOCUS);
+       output_channels.set_digits (0);
+       output_channels.set_wrap (false);
+       output_channels.set_editable (true);
+
+       if (!ARDOUR::Profile->get_mixbus()) {
+               label = manage (left_aligned_label (_("Output Channels:")));
+               basic_packer.attach (*label, 0, 1, row, row+1, xopt, (AttachOptions) 0);
+               basic_packer.attach (output_channels, 1, 2, row, row+1, xopt, (AttachOptions) 0);
+               ++row;
+       }
        
-       sr_connection.unblock ();
-}      
+       input_latency.set_name ("InputLatency");
+       input_latency.set_flags (Gtk::CAN_FOCUS);
+       input_latency.set_digits (0);
+       input_latency.set_wrap (false);
+       input_latency.set_editable (true);
+
+       label = manage (left_aligned_label (_("Hardware input latency:")));
+       basic_packer.attach (*label, 0, 1, row, row+1, xopt, (AttachOptions) 0);
+       basic_packer.attach (input_latency, 1, 2, row, row+1, xopt, (AttachOptions) 0);
+       label = manage (left_aligned_label (_("samples")));
+       basic_packer.attach (*label, 2, 3, row, row+1, SHRINK, (AttachOptions) 0);
+       ++row;
+
+       output_latency.set_name ("OutputLatency");
+       output_latency.set_flags (Gtk::CAN_FOCUS);
+       output_latency.set_digits (0);
+       output_latency.set_wrap (false);
+       output_latency.set_editable (true);
+
+       label = manage (left_aligned_label (_("Hardware output latency:")));
+       basic_packer.attach (*label, 0, 1, row, row+1, xopt, (AttachOptions) 0);
+       basic_packer.attach (output_latency, 1, 2, row, row+1, xopt, (AttachOptions) 0);
+       label = manage (left_aligned_label (_("samples")));
+       basic_packer.attach (*label, 2, 3, row, row+1, SHRINK, (AttachOptions) 0);
+
+       /* button spans 2 rows */
+
+       basic_packer.attach (lm_button_audio, 3, 4, row-1, row+1, xopt, xopt);
+       ++row;
+
+       label = manage (left_aligned_label (_("MIDI System:")));
+       basic_packer.attach (*label, 0, 1, row, row + 1, xopt, (AttachOptions) 0);
+       basic_packer.attach (midi_option_combo, 1, 2, row, row + 1, SHRINK, (AttachOptions) 0);
+       basic_packer.attach (midi_devices_button, 3, 4, row, row+1, xopt, xopt);
+       row++;
+}
 
 void
-EngineControl::reshow_buffer_sizes ()
+EngineControl::build_no_control_notebook ()
 {
        boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
        assert (backend);
-       string device_name = interface_combo.get_active_text ();
-       vector<string> s;
 
-       /* buffer sizes */
+       using namespace Notebook_Helpers;
+       Label* label;
+       vector<string> strings;
+       AttachOptions xopt = AttachOptions (FILL|EXPAND);
+       int row = 1; // row zero == backend combo
+       const string msg = string_compose (_("%1 is already running. %2 will connect to it and use the existing settings."), backend->name(), PROGRAM_NAME);
 
-       s.clear ();
-       vector<uint32_t> bs = backend->available_buffer_sizes(device_name);
-       uint32_t rate = get_rate();
+       label = manage (new Label);
+       label->set_markup (string_compose ("<span weight=\"bold\" foreground=\"red\">%1</span>", msg));
+       basic_packer.attach (*label, 0, 2, row, row + 1, xopt, (AttachOptions) 0);
+       row++;
 
-       for (vector<uint32_t>::const_iterator x = bs.begin(); x != bs.end(); ++x) {
-               char buf[32];
-               /* Translators: "samples" is ALWAYS plural here, so we do not
-                  need singular form as well. Same for msecs.
-               */
-               snprintf (buf, sizeof (buf), _("%u samples (%.1f msecs)"), *x, (2 * (*x)) / (rate/1000.0));
-               s.push_back (buf);
+       if (backend->can_change_sample_rate_when_running()) {
+               label = manage (left_aligned_label (_("Sample rate:")));
+               basic_packer.attach (*label, 0, 1, row, row + 1, xopt, (AttachOptions) 0);
+               basic_packer.attach (sample_rate_combo, 1, 2, row, row + 1, xopt, (AttachOptions) 0);
+               row++;
+       }
+
+       if (backend->can_change_buffer_size_when_running()) {
+               label = manage (left_aligned_label (_("Buffer size:")));
+               basic_packer.attach (*label, 0, 1, row, row + 1, xopt, (AttachOptions) 0);
+               basic_packer.attach (buffer_size_combo, 1, 2, row, row + 1, xopt, (AttachOptions) 0);
+               buffer_size_duration_label.set_alignment (0.0); /* left-align */
+               basic_packer.attach (buffer_size_duration_label, 2, 3, row, row+1, xopt, (AttachOptions) 0);
+               row++;
        }
 
-       set_popdown_strings (buffer_size_combo, s);
-       buffer_size_combo.set_active_text (s.front());
+       basic_packer.attach (connect_disconnect_button, 0, 2, row, row+1, FILL, AttachOptions (0));
+       row++;
 }
 
-void
-EngineControl::audio_mode_changed ()
+EngineControl::~EngineControl ()
 {
-       std::string str = audio_mode_combo.get_active_text();
-
-       if (str == _("Playback/recording on 1 device")) {
-               input_device_combo.set_sensitive (false);
-               output_device_combo.set_sensitive (false);
-       } else if (str == _("Playback/recording on 2 devices")) {
-               input_device_combo.set_sensitive (true);
-               output_device_combo.set_sensitive (true);
-       } else if (str == _("Playback only")) {
-               output_device_combo.set_sensitive (true);
-               input_device_combo.set_sensitive (false);
-       } else if (str == _("Recording only")) {
-               input_device_combo.set_sensitive (true);
-               output_device_combo.set_sensitive (false);
-       }
+       ignore_changes = true;
 }
 
-XMLNode&
-EngineControl::get_state ()
+void
+EngineControl::disable_latency_tab ()
 {
-       XMLNode* root = new XMLNode ("AudioSetup");
-       XMLNode* child;
-       std::string path;
+       vector<string> empty;
+       set_popdown_strings (lm_output_channel_combo, empty);
+       set_popdown_strings (lm_input_channel_combo, empty);
+       lm_measure_button.set_sensitive (false);
+       lm_use_button.set_sensitive (false);
+}
 
-#if 0
-       child = new XMLNode ("periods");
-       child->add_property ("val", to_string (periods_adjustment.get_value(), std::dec));
-       root->add_child_nocopy (*child);
+void
+EngineControl::enable_latency_tab ()
+{
+       vector<string> outputs;
+       vector<string> inputs;
 
-       child = new XMLNode ("ports");
-       child->add_property ("val", to_string (ports_adjustment.get_value(), std::dec));
-       root->add_child_nocopy (*child);
+       ARDOUR::DataType const type = _measure_midi ? ARDOUR::DataType::MIDI : ARDOUR::DataType::AUDIO;
+       ARDOUR::AudioEngine::instance()->get_physical_outputs (type, outputs);
+       ARDOUR::AudioEngine::instance()->get_physical_inputs (type, inputs);
 
-       child = new XMLNode ("inlatency");
-       child->add_property ("val", to_string (input_latency.get_value(), std::dec));
-       root->add_child_nocopy (*child);
+       if (!ARDOUR::AudioEngine::instance()->running()) {
+               MessageDialog msg (_("Failed to start or connect to audio-engine.\n\nLatency calibration requires a working audio interface."));
+               notebook.set_current_page (0);
+               msg.run ();
+               return;
+       }
+       else if (inputs.empty() || outputs.empty()) {
+               MessageDialog msg (_("Your selected audio configuration is playback- or capture-only.\n\nLatency calibration requires playback and capture"));
+               notebook.set_current_page (0);
+               msg.run ();
+               return;
+       }
 
-       child = new XMLNode ("outlatency");
-       child->add_property ("val", to_string (output_latency.get_value(), std::dec));
-       root->add_child_nocopy (*child);
+       lm_back_button_signal.disconnect();
+       if (_measure_midi) {
+               lm_back_button_signal = lm_back_button.signal_clicked().connect (sigc::bind (sigc::mem_fun (notebook, &Gtk::Notebook::set_current_page), midi_tab));
+               lm_preamble.hide ();
+       } else {
+               lm_back_button_signal = lm_back_button.signal_clicked().connect (sigc::bind (sigc::mem_fun (notebook, &Gtk::Notebook::set_current_page), 0));
+               lm_preamble.show ();
+       }
 
-       child = new XMLNode ("realtime");
-       child->add_property ("val", to_string (realtime_button.get_active(), std::dec));
-       root->add_child_nocopy (*child);
+       set_popdown_strings (lm_output_channel_combo, outputs);
+       lm_output_channel_combo.set_active_text (outputs.front());
+       lm_output_channel_combo.set_sensitive (true);
 
-       child = new XMLNode ("nomemorylock");
-       child->add_property ("val", to_string (no_memory_lock_button.get_active(), std::dec));
-       root->add_child_nocopy (*child);
+       set_popdown_strings (lm_input_channel_combo, inputs);
+       lm_input_channel_combo.set_active_text (inputs.front());
+       lm_input_channel_combo.set_sensitive (true);
 
-       child = new XMLNode ("unlockmemory");
-       child->add_property ("val", to_string (unlock_memory_button.get_active(), std::dec));
-       root->add_child_nocopy (*child);
+       lm_measure_button.set_sensitive (true);
+}
 
-       child = new XMLNode ("softmode");
-       child->add_property ("val", to_string (soft_mode_button.get_active(), std::dec));
-       root->add_child_nocopy (*child);
+void
+EngineControl::setup_midi_tab_for_backend ()
+{
+       string backend = backend_combo.get_active_text ();
 
-       child = new XMLNode ("force16bit");
-       child->add_property ("val", to_string (force16bit_button.get_active(), std::dec));
-       root->add_child_nocopy (*child);
+       Gtkmm2ext::container_clear (midi_vbox);
 
-       child = new XMLNode ("hwmonitor");
-       child->add_property ("val", to_string (hw_monitor_button.get_active(), std::dec));
-       root->add_child_nocopy (*child);
+       midi_vbox.set_border_width (12);
+       midi_device_table.set_border_width (12);
 
-       child = new XMLNode ("hwmeter");
-       child->add_property ("val", to_string (hw_meter_button.get_active(), std::dec));
-       root->add_child_nocopy (*child);
+       if (backend == "JACK") {
+               setup_midi_tab_for_jack ();
+       }
 
-       child = new XMLNode ("verbose");
-       child->add_property ("val", to_string (verbose_output_button.get_active(), std::dec));
-       root->add_child_nocopy (*child);
+       midi_vbox.pack_start (midi_device_table, true, true);
+       midi_vbox.pack_start (midi_back_button, false, false);
+       midi_vbox.show_all ();
+}
 
-       child = new XMLNode ("samplerate");
-       child->add_property ("val", sample_rate_combo.get_active_text());
-       root->add_child_nocopy (*child);
+void
+EngineControl::setup_midi_tab_for_jack ()
+{
+}
 
-       child = new XMLNode ("periodsize");
-       child->add_property ("val", period_size_combo.get_active_text());
-       root->add_child_nocopy (*child);
+void
+EngineControl::midi_latency_adjustment_changed (Gtk::Adjustment *a, MidiDeviceSettings device, bool for_input) {
+       if (for_input) {
+               device->input_latency = a->get_value();
+       } else {
+               device->output_latency = a->get_value();
+       }
+}
 
-       child = new XMLNode ("serverpath");
-       child->add_property ("val", serverpath_combo.get_active_text());
-       root->add_child_nocopy (*child);
+void
+EngineControl::midi_device_enabled_toggled (ArdourButton *b, MidiDeviceSettings device) {
+       b->set_active (!b->get_active());
+       device->enabled = b->get_active();
+       refresh_midi_display(device->name);
+}
 
-       child = new XMLNode ("driver");
-       child->add_property ("val", driver_combo.get_active_text());
-       root->add_child_nocopy (*child);
+void
+EngineControl::refresh_midi_display (std::string focus)
+{
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       assert (backend);
 
-       child = new XMLNode ("interface");
-       child->add_property ("val", interface_combo.get_active_text());
-       root->add_child_nocopy (*child);
+       int row  = 0;
+       AttachOptions xopt = AttachOptions (FILL|EXPAND);
+       Gtk::Label* l;
 
-       child = new XMLNode ("timeout");
-       child->add_property ("val", timeout_combo.get_active_text());
-       root->add_child_nocopy (*child);
+       Gtkmm2ext::container_clear (midi_device_table);
 
-       child = new XMLNode ("dither");
-       child->add_property ("val", dither_mode_combo.get_active_text());
-       root->add_child_nocopy (*child);
+       midi_device_table.set_spacings (6);
 
-       child = new XMLNode ("audiomode");
-       child->add_property ("val", audio_mode_combo.get_active_text());
-       root->add_child_nocopy (*child);
+       l = manage (new Label);
+       l->set_markup (string_compose ("<span size=\"large\" weight=\"bold\">%1</span>", _("MIDI Devices")));
+       midi_device_table.attach (*l, 0, 4, row, row + 1, xopt, AttachOptions (0));
+       l->set_alignment (0.5, 0.5);
+       row++;
+       l->show ();
 
-       child = new XMLNode ("inputdevice");
-       child->add_property ("val", input_device_combo.get_active_text());
-       root->add_child_nocopy (*child);
+       l = manage (new Label (_("Device"))); l->show (); l->set_alignment (0.5, 0.5);
+       midi_device_table.attach (*l, 0, 1, row, row + 2, xopt, AttachOptions (0));
+       l = manage (new Label (_("Hardware Latencies"))); l->show (); l->set_alignment (0.5, 0.5);
+       midi_device_table.attach (*l, 1, 3, row, row + 1, xopt, AttachOptions (0));
+       row++;
+       l = manage (new Label (_("Input"))); l->show (); l->set_alignment (0.5, 0.5);
+       midi_device_table.attach (*l, 1, 2, row, row + 1, xopt, AttachOptions (0));
+       l = manage (new Label (_("Output"))); l->show (); l->set_alignment (0.5, 0.5);
+       midi_device_table.attach (*l, 2, 3, row, row + 1, xopt, AttachOptions (0));
+       row++;
 
-       child = new XMLNode ("outputdevice");
-       child->add_property ("val", output_device_combo.get_active_text());
-       root->add_child_nocopy (*child);
+       for (vector<MidiDeviceSettings>::const_iterator p = _midi_devices.begin(); p != _midi_devices.end(); ++p) {
+               ArdourButton *m;
+               Gtk::Button* b;
+               Gtk::Adjustment *a;
+               Gtk::SpinButton *s;
+               bool enabled = (*p)->enabled;
+
+               m = manage (new ArdourButton ((*p)->name, ArdourButton::led_default_elements));
+               m->set_name ("midi device");
+               m->set_can_focus (Gtk::CAN_FOCUS);
+               m->add_events (Gdk::BUTTON_RELEASE_MASK);
+               m->set_active (enabled);
+               m->signal_clicked.connect (sigc::bind (sigc::mem_fun (*this, &EngineControl::midi_device_enabled_toggled), m, *p));
+               midi_device_table.attach (*m, 0, 1, row, row + 1, xopt, AttachOptions (0)); m->show ();
+               if ((*p)->name == focus) {
+                       m->grab_focus();
+               }
 
-       child = new XMLNode ("mididriver");
-       child->add_property ("val", midi_driver_combo.get_active_text());
-       root->add_child_nocopy (*child);
-#endif
-       return *root;
+               a = manage (new Gtk::Adjustment (0, 0, 99999, 1));
+               s = manage (new Gtk::SpinButton (*a));
+               a->set_value ((*p)->input_latency);
+               s->signal_value_changed().connect (sigc::bind (sigc::mem_fun (*this, &EngineControl::midi_latency_adjustment_changed), a, *p, true));
+               s->set_sensitive (_can_set_midi_latencies && enabled);
+               midi_device_table.attach (*s, 1, 2, row, row + 1, xopt, AttachOptions (0)); s->show ();
+
+               a = manage (new Gtk::Adjustment (0, 0, 99999, 1));
+               s = manage (new Gtk::SpinButton (*a));
+               a->set_value ((*p)->output_latency);
+               s->signal_value_changed().connect (sigc::bind (sigc::mem_fun (*this, &EngineControl::midi_latency_adjustment_changed), a, *p, false));
+               s->set_sensitive (_can_set_midi_latencies && enabled);
+               midi_device_table.attach (*s, 2, 3, row, row + 1, xopt, AttachOptions (0)); s->show ();
+
+               b = manage (new Button (_("Calibrate")));
+               b->signal_clicked().connect (sigc::bind (sigc::mem_fun (*this, &EngineControl::calibrate_midi_latency), *p));
+               b->set_sensitive (_can_set_midi_latencies && enabled);
+               midi_device_table.attach (*b, 3, 4, row, row + 1, xopt, AttachOptions (0)); b->show ();
+
+               row++;
+       }
 }
 
 void
-EngineControl::set_state (const XMLNode& root)
+EngineControl::backend_changed ()
 {
-#if 0
-       XMLNodeList          clist;
-       XMLNodeConstIterator citer;
-       XMLNode* child;
-       XMLProperty* prop = NULL;
-       bool using_dummy = false;
-       bool using_ffado = false;
-
-       int val;
-       string strval;
+       DEBUG_ECONTROL ("backend_changed");
 
-       if ( (child = root.child ("driver"))){
-               prop = child->property("val");
-
-               if (prop && (prop->value() == "Dummy") ) {
-                       using_dummy = true;
-               }
-               if (prop && (prop->value() == "FFADO") ) {
-                       using_ffado = true;
-               }
+       string backend_name = backend_combo.get_active_text();
+       boost::shared_ptr<ARDOUR::AudioBackend> backend;
 
+       if (!(backend = ARDOUR::AudioEngine::instance()->set_backend (backend_name, "ardour", ""))) {
+               /* eh? setting the backend failed... how ? */
+               /* A: stale config contains a backend that does not exist in current build */
+               return;
        }
 
-       clist = root.children();
-
-       for (citer = clist.begin(); citer != clist.end(); ++citer) {
+       DEBUG_ECONTROL (string_compose ("Backend name: %1", backend_name));
 
-               child = *citer;
+       _have_control = ARDOUR::AudioEngine::instance()->setup_required ();
 
-               prop = child->property ("val");
+       build_notebook ();
+       setup_midi_tab_for_backend ();
+       _midi_devices.clear();
 
-               if (!prop || prop->value().empty()) {
+       if (backend->requires_driver_selection()) {
+               vector<string> drivers = backend->enumerate_drivers();
+               driver_combo.set_sensitive (true);
 
-                       if (((using_dummy || using_ffado)
-                               && ( child->name() == "interface"
-                                       || child->name() == "inputdevice"
-                                       || child->name() == "outputdevice"))
-                               || child->name() == "timeout")
+               if (!drivers.empty()) {
                        {
-                               continue;
+                               string current_driver;
+                               current_driver = backend->driver_name ();
+
+                               DEBUG_ECONTROL (string_compose ("backend->driver_name: %1", current_driver));
+
+                               // driver might not have been set yet
+                               if (current_driver == "") {
+                                       current_driver = driver_combo.get_active_text ();
+                                       if (current_driver == "")
+                                               // driver has never been set, make sure it's not blank
+                                               current_driver = drivers.front ();
+                               }
+
+                               PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+                               set_popdown_strings (driver_combo, drivers);
+                               DEBUG_ECONTROL (
+                                   string_compose ("driver_combo.set_active_text: %1", current_driver));
+                               driver_combo.set_active_text (current_driver);
                        }
 
-                       error << string_compose (_("AudioSetup value for %1 is missing data"), child->name()) << endmsg;
-                       continue;
+                       driver_changed ();
                }
 
-               strval = prop->value();
-
-               /* adjustments/spinners */
-
-               if (child->name() == "periods") {
-                       val = atoi (strval);
-                       periods_adjustment.set_value(val);
-               } else if (child->name() == "ports") {
-                       val = atoi (strval);
-                       ports_adjustment.set_value(val);
-               } else if (child->name() == "inlatency") {
-                       val = atoi (strval);
-                       input_latency.set_value(val);
-               } else if (child->name() == "outlatency") {
-                       val = atoi (strval);
-                       output_latency.set_value(val);
-               }
-
-               /* buttons */
-
-               else if (child->name() == "realtime") {
-                       val = atoi (strval);
-                       realtime_button.set_active(val);
-               } else if (child->name() == "nomemorylock") {
-                       val = atoi (strval);
-                       no_memory_lock_button.set_active(val);
-               } else if (child->name() == "unlockmemory") {
-                       val = atoi (strval);
-                       unlock_memory_button.set_active(val);
-               } else if (child->name() == "softmode") {
-                       val = atoi (strval);
-                       soft_mode_button.set_active(val);
-               } else if (child->name() == "force16bit") {
-                       val = atoi (strval);
-                       force16bit_button.set_active(val);
-               } else if (child->name() == "hwmonitor") {
-                       val = atoi (strval);
-                       hw_monitor_button.set_active(val);
-               } else if (child->name() == "hwmeter") {
-                       val = atoi (strval);
-                       hw_meter_button.set_active(val);
-               } else if (child->name() == "verbose") {
-                       val = atoi (strval);
-                       verbose_output_button.set_active(val);
-               }
-
-               /* combos */
-
-               else if (child->name() == "samplerate") {
-                       sample_rate_combo.set_active_text(strval);
-               } else if (child->name() == "periodsize") {
-                       period_size_combo.set_active_text(strval);
-               } else if (child->name() == "serverpath") {
-
-                        /* only attempt to set this if we have bothered to look
-                           up server names already. otherwise this is all
-                           redundant (actually, all of this dialog/widget
-                           is redundant in that case ...)
-                        */
-
-                        if (!server_strings.empty()) {
-                                /* do not allow us to use a server path that doesn't
-                                   exist on this system. this handles cases where
-                                   the user has an RC file listing a serverpath
-                                   from some other machine.
-                                */
-                                vector<string>::iterator x;
-                                for (x = server_strings.begin(); x != server_strings.end(); ++x) {
-                                        if (*x == strval) {
-                                                break;
-                                        }
-                                }
-                                if (x != server_strings.end()) {
-                                        serverpath_combo.set_active_text (strval);
-                                } else {
-                                        warning << string_compose (_("configuration files contain a JACK server path that doesn't exist (%1)"),
-                                                                   strval)
-                                                << endmsg;
-                                }
-                        }
-
-               } else if (child->name() == "driver") {
-                       driver_combo.set_active_text(strval);
-               } else if (child->name() == "interface") {
-                       interface_combo.set_active_text(strval);
-               } else if (child->name() == "timeout") {
-                       timeout_combo.set_active_text(strval);
-               } else if (child->name() == "dither") {
-                       dither_mode_combo.set_active_text(strval);
-               } else if (child->name() == "audiomode") {
-                       audio_mode_combo.set_active_text(strval);
-               } else if (child->name() == "inputdevice") {
-                       input_device_combo.set_active_text(strval);
-               } else if (child->name() == "outputdevice") {
-                       output_device_combo.set_active_text(strval);
-               } else if (child->name() == "mididriver") {
-                       midi_driver_combo.set_active_text(strval);
-               }
+       } else {
+               driver_combo.set_sensitive (false);
+               /* this will change the device text which will cause a call to
+                * device changed which will set up parameters
+                */
+               list_devices ();
        }
+
+       update_midi_options ();
+
+       connect_disconnect_button.hide();
+
+       midi_option_changed();
+
+       started_at_least_once = false;
+
+       if (!ignore_changes) {
+               maybe_display_saved_state ();
+       }
+}
+
+void
+EngineControl::update_midi_options ()
+{
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       vector<string> midi_options = backend->enumerate_midi_options();
+
+       if (midi_options.size() == 1) {
+               /* only contains the "none" option */
+               midi_option_combo.set_sensitive (false);
+       } else {
+               if (_have_control) {
+                       set_popdown_strings (midi_option_combo, midi_options);
+                       midi_option_combo.set_active_text (midi_options.front());
+                       midi_option_combo.set_sensitive (true);
+               } else {
+                       midi_option_combo.set_sensitive (false);
+               }
+       }
+}
+
+bool
+EngineControl::print_channel_count (Gtk::SpinButton* sb)
+{
+       if (ARDOUR::Profile->get_mixbus()) {
+               return true;
+       }
+       
+       uint32_t cnt = (uint32_t) sb->get_value();
+       if (cnt == 0) {
+               sb->set_text (_("all available channels"));
+       } else {
+               char buf[32];
+               snprintf (buf, sizeof (buf), "%d", cnt);
+               sb->set_text (buf);
+       }
+       return true;
+}
+
+bool
+EngineControl::set_driver_popdown_strings ()
+{
+       DEBUG_ECONTROL ("set_driver_popdown_strings");
+       string backend_name = backend_combo.get_active_text();
+       boost::shared_ptr<ARDOUR::AudioBackend> backend;
+
+       if (!(backend = ARDOUR::AudioEngine::instance()->set_backend (backend_name, "ardour", ""))) {
+               /* eh? setting the backend failed... how ? */
+               /* A: stale config contains a backend that does not exist in current build */
+               return false;
+       }
+
+       vector<string> drivers = backend->enumerate_drivers();
+       set_popdown_strings (driver_combo, drivers);
+       return true;
+}
+
+// @return true if there are devices available
+bool
+EngineControl::set_device_popdown_strings ()
+{
+       DEBUG_ECONTROL ("set_device_popdown_strings");
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       vector<ARDOUR::AudioBackend::DeviceStatus> all_devices = backend->enumerate_devices ();
+
+       /* NOTE: Ardour currently does not display the "available" field of the
+        * returned devices.
+        *
+        * Doing so would require a different GUI widget than the combo
+        * box/popdown that we currently use, since it has no way to list
+        * items that are not selectable. Something more like a popup menu,
+        * which could have unselectable items, would be appropriate.
+        */
+
+       vector<string> available_devices;
+
+       for (vector<ARDOUR::AudioBackend::DeviceStatus>::const_iterator i = all_devices.begin(); i != all_devices.end(); ++i) {
+               available_devices.push_back (i->name);
+       }
+
+
+       if (!available_devices.empty()) {
+
+               {
+                       string current_device, found_device;
+                       current_device = device_combo.get_active_text ();
+                       if (current_device == "") {
+                               current_device = backend->device_name ();
+                       }
+
+                       // Make sure that the active text is still relevant for this
+                       // device (it might only be relevant to the previous device!!)
+                       for (vector<string>::const_iterator i = available_devices.begin(); i != available_devices.end(); ++i) {
+                               if (*i == current_device)
+                                       found_device = current_device;
+                       }
+                       if (found_device == "")
+                               // device has never been set (or was not relevant
+                               // for this backend) Let's make sure it's not blank
+                               current_device = available_devices.front ();
+
+                       PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+                       set_popdown_strings (device_combo, available_devices);
+                       DEBUG_ECONTROL (string_compose ("set device_combo active text: %1", current_device));
+
+                       device_combo.set_active_text (current_device);
+               }
+               return true;
+       }
+       return false;
+}
+
+// @return true if there are input devices available
+bool
+EngineControl::set_input_device_popdown_strings ()
+{
+       DEBUG_ECONTROL ("set_input_device_popdown_strings");
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       vector<ARDOUR::AudioBackend::DeviceStatus> all_devices = backend->enumerate_input_devices ();
+
+       vector<string> available_devices;
+
+       for (vector<ARDOUR::AudioBackend::DeviceStatus>::const_iterator i = all_devices.begin(); i != all_devices.end(); ++i) {
+               available_devices.push_back (i->name);
+       }
+
+       if (!available_devices.empty()) {
+
+               {
+                       string current_device, found_device;
+                       current_device = input_device_combo.get_active_text ();
+                       if (current_device == "") {
+                               current_device = backend->input_device_name ();
+                       }
+
+                       // Make sure that the active text is still relevant for this
+                       // device (it might only be relevant to the previous device!!)
+                       for (vector<string>::const_iterator i = available_devices.begin(); i != available_devices.end(); ++i) {
+                               if (*i == current_device)
+                                       found_device = current_device;
+                       }
+                       if (found_device == "")
+                               // device has never been set (or was not relevant
+                               // for this backend) Let's make sure it's not blank
+                               current_device = available_devices.front ();
+
+                       PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+                       set_popdown_strings (input_device_combo, available_devices);
+
+                       DEBUG_ECONTROL (string_compose ("set input_device_combo active text: %1", current_device));
+                       input_device_combo.set_active_text (current_device);
+               }
+               return true;
+       }
+
+       return false;
+}
+
+// @return true if there are output devices available
+bool
+EngineControl::set_output_device_popdown_strings ()
+{
+       DEBUG_ECONTROL ("set_output_device_popdown_strings");
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       vector<ARDOUR::AudioBackend::DeviceStatus> all_devices = backend->enumerate_output_devices ();
+
+       vector<string> available_devices;
+
+       for (vector<ARDOUR::AudioBackend::DeviceStatus>::const_iterator i = all_devices.begin(); i != all_devices.end(); ++i) {
+               available_devices.push_back (i->name);
+       }
+
+       if (!available_devices.empty()) {
+
+               {
+                       string current_device, found_device;
+                       current_device = output_device_combo.get_active_text ();
+                       if (current_device == "") {
+                               current_device = backend->output_device_name ();
+                       }
+
+                       // Make sure that the active text is still relevant for this
+                       // device (it might only be relevant to the previous device!!)
+                       for (vector<string>::const_iterator i = available_devices.begin(); i != available_devices.end(); ++i) {
+                               if (*i == current_device)
+                                       found_device = current_device;
+                       }
+                       if (found_device == "")
+                               // device has never been set (or was not relevant
+                               // for this backend) Let's make sure it's not blank
+                               current_device = available_devices.front ();
+
+                       PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+                       set_popdown_strings (output_device_combo, available_devices);
+
+                       DEBUG_ECONTROL (string_compose ("set input_device_combo active text: %1", current_device));
+                       output_device_combo.set_active_text (current_device);
+               }
+               return true;
+       }
+
+       return false;
+}
+
+void
+EngineControl::list_devices ()
+{
+       DEBUG_ECONTROL ("list_devices");
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       assert (backend);
+
+       /* now fill out devices, mark sample rates, buffer sizes insensitive */
+
+       bool devices_available = false;
+
+       if (backend->use_separate_input_and_output_devices ()) {
+               bool input_devices_available = set_input_device_popdown_strings ();
+               bool output_devices_available = set_output_device_popdown_strings ();
+               devices_available = input_devices_available || output_devices_available;
+       } else {
+               devices_available = set_device_popdown_strings ();
+       }
+
+       if (devices_available) {
+               device_changed ();
+
+               input_latency.set_sensitive (true);
+               output_latency.set_sensitive (true);
+               input_channels.set_sensitive (true);
+               output_channels.set_sensitive (true);
+
+               ok_button->set_sensitive (true);
+               apply_button->set_sensitive (true);
+
+       } else {
+               device_combo.clear();
+               input_device_combo.clear();
+               output_device_combo.clear();
+               sample_rate_combo.set_sensitive (false);
+               buffer_size_combo.set_sensitive (false);
+               input_latency.set_sensitive (false);
+               output_latency.set_sensitive (false);
+               input_channels.set_sensitive (false);
+               output_channels.set_sensitive (false);
+               if (_have_control) {
+                       ok_button->set_sensitive (false);
+                       apply_button->set_sensitive (false);
+               } else {
+                       ok_button->set_sensitive (true);
+                       apply_button->set_sensitive (true);
+                       if (backend->can_change_sample_rate_when_running() && sample_rate_combo.get_children().size() > 0) {
+                               sample_rate_combo.set_sensitive (true);
+                       }
+                       if (backend->can_change_buffer_size_when_running() && buffer_size_combo.get_children().size() > 0) {
+                               buffer_size_combo.set_sensitive (true);
+                       }
+
+               }
+       }
+}
+
+void
+EngineControl::driver_changed ()
+{
+       DEBUG_ECONTROL ("driver_changed");
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       assert (backend);
+
+       backend->set_driver (driver_combo.get_active_text());
+       list_devices ();
+
+       if (!ignore_changes) {
+               maybe_display_saved_state ();
+       }
+}
+
+void
+EngineControl::set_samplerate_popdown_strings (const std::string& device_name)
+{
+       DEBUG_ECONTROL ("set_samplerate_popdown_strings");
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       string desired;
+       vector<float> sr;
+       vector<string> s;
+
+       if (_have_control) {
+               sr = backend->available_sample_rates (device_name);
+       } else {
+
+               sr.push_back (8000.0f);
+               sr.push_back (16000.0f);
+               sr.push_back (32000.0f);
+               sr.push_back (44100.0f);
+               sr.push_back (48000.0f);
+               sr.push_back (88200.0f);
+               sr.push_back (96000.0f);
+               sr.push_back (192000.0f);
+               sr.push_back (384000.0f);
+       }
+
+       for (vector<float>::const_iterator x = sr.begin(); x != sr.end(); ++x) {
+               s.push_back (rate_as_string (*x));
+               if (*x == _desired_sample_rate) {
+                       desired = s.back();
+               }
+       }
+
+       if (!s.empty()) {
+               sample_rate_combo.set_sensitive (true);
+               set_popdown_strings (sample_rate_combo, s);
+
+               if (desired.empty()) {
+                       sample_rate_combo.set_active_text (rate_as_string (backend->default_sample_rate()));
+               } else {
+                       sample_rate_combo.set_active_text (desired);
+               }
+
+       } else {
+               sample_rate_combo.set_sensitive (false);
+       }
+}
+
+void
+EngineControl::set_buffersize_popdown_strings (const std::string& device_name)
+{
+       DEBUG_ECONTROL ("set_buffersize_popdown_strings");
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       vector<uint32_t> bs;
+       vector<string> s;
+
+       if (_have_control) {
+               bs = backend->available_buffer_sizes (device_name);
+       } else if (backend->can_change_buffer_size_when_running()) {
+               bs.push_back (8);
+               bs.push_back (16);
+               bs.push_back (32);
+               bs.push_back (64);
+               bs.push_back (128);
+               bs.push_back (256);
+               bs.push_back (512);
+               bs.push_back (1024);
+               bs.push_back (2048);
+               bs.push_back (4096);
+               bs.push_back (8192);
+       }
+       s.clear ();
+       for (vector<uint32_t>::const_iterator x = bs.begin(); x != bs.end(); ++x) {
+               s.push_back (bufsize_as_string (*x));
+       }
+
+       if (!s.empty()) {
+               buffer_size_combo.set_sensitive (true);
+               set_popdown_strings (buffer_size_combo, s);
+               buffer_size_combo.set_active_text (s.front());
+
+               uint32_t period = backend->buffer_size();
+               if (0 == period) {
+                       period = backend->default_buffer_size(device_name);
+               }
+               set_active_text_if_present (buffer_size_combo, bufsize_as_string (period));
+               show_buffer_duration ();
+       } else {
+               buffer_size_combo.set_sensitive (false);
+       }
+}
+
+void
+EngineControl::device_changed ()
+{
+       DEBUG_ECONTROL ("device_changed");
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       assert (backend);
+
+       string device_name_in;
+       string device_name_out; // only used if backend support separate I/O devices
+
+       if (backend->use_separate_input_and_output_devices()) {
+               device_name_in  = get_input_device_name ();
+               device_name_out = get_output_device_name ();
+       } else {
+               device_name_in = get_device_name ();
+       }
+
+       /* we set the backend-device to query various device related intormation.
+        * This has the side effect that backend->device_name() will match
+        * the device_name and  'change_device' will never be true.
+        * so work around this by setting...
+        */
+       if (backend->use_separate_input_and_output_devices()) {
+               if (device_name_in != backend->input_device_name() || device_name_out != backend->output_device_name ()) {
+                       queue_device_changed = true;
+               }
+       } else {
+               if (device_name_in != backend->device_name()) {
+                       queue_device_changed = true;
+               }
+       }
+       
+       //the device name must be set FIRST so ASIO can populate buffersizes and the control panel button
+       if (backend->use_separate_input_and_output_devices()) {
+               backend->set_input_device_name (device_name_in);
+               backend->set_output_device_name (device_name_out);
+       } else {
+               backend->set_device_name(device_name_in);
+       }
+
+       {
+               /* don't allow programmatic change to combos to cause a
+                  recursive call to this method.
+                */
+               PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+
+               /* backends that support separate devices, need to ignore
+                * the device-name - and use the devies set above
+                */
+               set_samplerate_popdown_strings (device_name_in);
+               set_buffersize_popdown_strings (device_name_in);
+               /* XXX theoretically need to set min + max channel counts here
+               */
+
+               manage_control_app_sensitivity ();
+       }
+
+       /* pick up any saved state for this device */
+
+       if (!ignore_changes) {
+               maybe_display_saved_state ();
+       }
+}
+
+void
+EngineControl::input_device_changed ()
+{
+       DEBUG_ECONTROL ("input_device_changed");
+       device_changed ();
+}
+
+void
+EngineControl::output_device_changed ()
+{
+       DEBUG_ECONTROL ("output_device_changed");
+       device_changed ();
+}
+
+string
+EngineControl::bufsize_as_string (uint32_t sz)
+{
+       /* Translators: "samples" is always plural here, so no
+          need for plural+singular forms.
+        */
+       char buf[64];
+       snprintf (buf, sizeof (buf), "%u %s", sz, P_("sample", "samples", sz));
+       return buf;
+}
+
+void
+EngineControl::sample_rate_changed ()
+{
+       DEBUG_ECONTROL ("sample_rate_changed");
+       /* reset the strings for buffer size to show the correct msec value
+          (reflecting the new sample rate).
+        */
+
+       show_buffer_duration ();
+
+}
+
+void
+EngineControl::buffer_size_changed ()
+{
+       DEBUG_ECONTROL ("buffer_size_changed");
+       show_buffer_duration ();
+}
+
+void
+EngineControl::show_buffer_duration ()
+{
+       DEBUG_ECONTROL ("show_buffer_duration");
+       /* buffer sizes  - convert from just samples to samples + msecs for
+        * the displayed string
+        */
+
+       string bs_text = buffer_size_combo.get_active_text ();
+       uint32_t samples = atoi (bs_text); /* will ignore trailing text */
+       uint32_t rate = get_rate();
+
+       /* Developers: note the hard-coding of a double buffered model
+          in the (2 * samples) computation of latency. we always start
+          the audiobackend in this configuration.
+        */
+       /* note to jack1 developers: ardour also always starts the engine
+        * in async mode (no jack2 --sync option) which adds an extra cycle
+        * of latency with jack2 (and *3 would be correct)
+        * The value can also be wrong if jackd is started externally..
+        *
+        * At the time of writing the ALSA backend always uses double-buffering *2,
+        * The Dummy backend *1, and who knows what ASIO really does :)
+        *
+        * So just display the period size, that's also what
+        * ARDOUR_UI::update_sample_rate() does for the status bar.
+        * (the statusbar calls AudioEngine::instance()->usecs_per_cycle()
+        * but still, that's the buffer period, not [round-trip] latency)
+        */
+       char buf[32];
+       snprintf (buf, sizeof (buf), _("(%.1f ms)"), (samples / (rate/1000.0f)));
+       buffer_size_duration_label.set_text (buf);
+}
+
+void
+EngineControl::midi_option_changed ()
+{
+       DEBUG_ECONTROL ("midi_option_changed");
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       assert (backend);
+
+       backend->set_midi_option (get_midi_option());
+
+       vector<ARDOUR::AudioBackend::DeviceStatus> midi_devices = backend->enumerate_midi_devices();
+
+       //_midi_devices.clear(); // TODO merge with state-saved settings..
+       _can_set_midi_latencies = backend->can_set_systemic_midi_latencies();
+       std::vector<MidiDeviceSettings> new_devices;
+
+       for (vector<ARDOUR::AudioBackend::DeviceStatus>::const_iterator i = midi_devices.begin(); i != midi_devices.end(); ++i) {
+               MidiDeviceSettings mds = find_midi_device (i->name);
+               if (i->available && !mds) {
+                       uint32_t input_latency = 0;
+                       uint32_t output_latency = 0;
+                       if (_can_set_midi_latencies) {
+                               input_latency = backend->systemic_midi_input_latency (i->name);
+                               output_latency = backend->systemic_midi_output_latency (i->name);
+                       }
+                       bool enabled = backend->midi_device_enabled (i->name);
+                       MidiDeviceSettings ptr (new MidiDeviceSetting (i->name, enabled, input_latency, output_latency));
+                       new_devices.push_back (ptr);
+               } else if (i->available) {
+                       new_devices.push_back (mds);
+               }
+       }
+       _midi_devices = new_devices;
+
+       if (_midi_devices.empty()) {
+               midi_devices_button.set_sensitive (false);
+       } else {
+               midi_devices_button.set_sensitive (true);
+       }
+}
+
+void
+EngineControl::parameter_changed ()
+{
+}
+
+EngineControl::State
+EngineControl::get_matching_state (
+               const string& backend,
+               const string& driver,
+               const string& device)
+{
+       for (StateList::iterator i = states.begin(); i != states.end(); ++i) {
+               if ((*i)->backend == backend &&
+                               (!_have_control || ((*i)->driver == driver && (*i)->device == device)))
+               {
+                       return (*i);
+               }
+       }
+       return State();
+}
+
+EngineControl::State
+EngineControl::get_matching_state (
+               const string& backend,
+               const string& driver,
+               const string& input_device,
+               const string& output_device)
+{
+       for (StateList::iterator i = states.begin(); i != states.end(); ++i) {
+               if ((*i)->backend == backend &&
+                               (!_have_control || ((*i)->driver == driver && ((*i)->input_device == input_device) && (*i)->output_device == output_device)))
+               {
+                       return (*i);
+               }
+       }
+       return State();
+}
+
+EngineControl::State
+EngineControl::get_saved_state_for_currently_displayed_backend_and_device ()
+{
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+
+       if (backend) {
+               if (backend->use_separate_input_and_output_devices ()) {
+                       return get_matching_state (backend_combo.get_active_text(),
+                                       (backend->requires_driver_selection() ? (std::string) driver_combo.get_active_text() : string()),
+                                       input_device_combo.get_active_text(),
+                                       output_device_combo.get_active_text());
+               } else {
+                       return get_matching_state (backend_combo.get_active_text(),
+                                       (backend->requires_driver_selection() ? (std::string) driver_combo.get_active_text() : string()),
+                                       device_combo.get_active_text());
+               }
+       }
+
+       return get_matching_state (backend_combo.get_active_text(),
+                       string(),
+                       device_combo.get_active_text());
+}
+
+bool EngineControl::equivalent_states (const EngineControl::State& state1,
+                                       const EngineControl::State& state2)
+{
+       if (state1->backend == state2->backend &&
+                       state1->driver == state2->driver &&
+                       state1->device == state2->device &&
+                       state1->input_device == state2->input_device &&
+                       state1->output_device == state2->output_device) {
+               return true;
+       }
+       return false;
+}
+
+EngineControl::State
+EngineControl::save_state ()
+{
+       State state;
+
+       if (!_have_control) {
+               state = get_matching_state (backend_combo.get_active_text(), string(), string());
+               if (state) {
+                       return state;
+               }
+               state.reset(new StateStruct);
+               state->backend = get_backend ();
+       } else {
+               state.reset(new StateStruct);
+               store_state (state);
+       }
+
+       for (StateList::iterator i = states.begin(); i != states.end();) {
+               if (equivalent_states (*i, state)) {
+                       i =  states.erase(i);
+               } else {
+                       ++i;
+               }
+       }
+
+       states.push_back (state);
+
+       return state;
+}
+
+void
+EngineControl::store_state (State state)
+{
+       state->backend = get_backend ();
+       state->driver = get_driver ();
+       state->device = get_device_name ();
+       state->input_device = get_input_device_name ();
+       state->output_device = get_output_device_name ();
+       state->sample_rate = get_rate ();
+       state->buffer_size = get_buffer_size ();
+       state->input_latency = get_input_latency ();
+       state->output_latency = get_output_latency ();
+       state->input_channels = get_input_channels ();
+       state->output_channels = get_output_channels ();
+       state->midi_option = get_midi_option ();
+       state->midi_devices = _midi_devices;
+}
+
+void
+EngineControl::maybe_display_saved_state ()
+{
+       if (!_have_control) {
+               return;
+       }
+
+       State state = get_saved_state_for_currently_displayed_backend_and_device ();
+
+       if (state) {
+               PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+
+               if (!_desired_sample_rate) {
+                       sample_rate_combo.set_active_text (rate_as_string (state->sample_rate));
+               }
+               set_active_text_if_present (buffer_size_combo, bufsize_as_string (state->buffer_size));
+               /* call this explicitly because we're ignoring changes to
+                  the controls at this point.
+                */
+               show_buffer_duration ();
+               input_latency.set_value (state->input_latency);
+               output_latency.set_value (state->output_latency);
+
+               if (!state->midi_option.empty()) {
+                       midi_option_combo.set_active_text (state->midi_option);
+                       _midi_devices = state->midi_devices;
+               }
+       }
+}
+
+XMLNode&
+EngineControl::get_state ()
+{
+       LocaleGuard lg (X_("C"));
+
+       XMLNode* root = new XMLNode ("AudioMIDISetup");
+       std::string path;
+
+       if (!states.empty()) {
+               XMLNode* state_nodes = new XMLNode ("EngineStates");
+
+               for (StateList::const_iterator i = states.begin(); i != states.end(); ++i) {
+
+                       XMLNode* node = new XMLNode ("State");
+
+                       node->add_property ("backend", (*i)->backend);
+                       node->add_property ("driver", (*i)->driver);
+                       node->add_property ("device", (*i)->device);
+                       node->add_property ("input-device", (*i)->input_device);
+                       node->add_property ("output-device", (*i)->output_device);
+                       node->add_property ("sample-rate", (*i)->sample_rate);
+                       node->add_property ("buffer-size", (*i)->buffer_size);
+                       node->add_property ("input-latency", (*i)->input_latency);
+                       node->add_property ("output-latency", (*i)->output_latency);
+                       node->add_property ("input-channels", (*i)->input_channels);
+                       node->add_property ("output-channels", (*i)->output_channels);
+                       node->add_property ("active", (*i)->active ? "yes" : "no");
+                       node->add_property ("midi-option", (*i)->midi_option);
+
+                       XMLNode* midi_devices = new XMLNode ("MIDIDevices");
+                       for (std::vector<MidiDeviceSettings>::const_iterator p = (*i)->midi_devices.begin(); p != (*i)->midi_devices.end(); ++p) {
+                               XMLNode* midi_device_stuff = new XMLNode ("MIDIDevice");
+                               midi_device_stuff->add_property (X_("name"), (*p)->name);
+                               midi_device_stuff->add_property (X_("enabled"), (*p)->enabled);
+                               midi_device_stuff->add_property (X_("input-latency"), (*p)->input_latency);
+                               midi_device_stuff->add_property (X_("output-latency"), (*p)->output_latency);
+                               midi_devices->add_child_nocopy (*midi_device_stuff);
+                       }
+                       node->add_child_nocopy (*midi_devices);
+
+                       state_nodes->add_child_nocopy (*node);
+               }
+
+               root->add_child_nocopy (*state_nodes);
+       }
+
+       return *root;
+}
+
+void
+EngineControl::set_state (const XMLNode& root)
+{
+       XMLNodeList          clist, cclist;
+       XMLNodeConstIterator citer, cciter;
+       XMLNode* child;
+       XMLNode* grandchild;
+       XMLProperty* prop = NULL;
+
+       fprintf (stderr, "EngineControl::set_state\n");
+
+       if (root.name() != "AudioMIDISetup") {
+               return;
+       }
+
+       clist = root.children();
+
+       states.clear ();
+
+       for (citer = clist.begin(); citer != clist.end(); ++citer) {
+
+               child = *citer;
+
+               if (child->name() != "EngineStates") {
+                       continue;
+               }
+
+               cclist = child->children();
+
+               for (cciter = cclist.begin(); cciter != cclist.end(); ++cciter) {
+                       State state (new StateStruct);
+
+                       grandchild = *cciter;
+
+                       if (grandchild->name() != "State") {
+                               continue;
+                       }
+
+                       if ((prop = grandchild->property ("backend")) == 0) {
+                               continue;
+                       }
+                       state->backend = prop->value ();
+
+                       if ((prop = grandchild->property ("driver")) == 0) {
+                               continue;
+                       }
+                       state->driver = prop->value ();
+
+                       if ((prop = grandchild->property ("device")) == 0) {
+                               continue;
+                       }
+                       state->device = prop->value ();
+
+                       if ((prop = grandchild->property ("input-device")) == 0) {
+                               continue;
+                       }
+                       state->input_device = prop->value ();
+
+                       if ((prop = grandchild->property ("output-device")) == 0) {
+                               continue;
+                       }
+                       state->output_device = prop->value ();
+
+                       if ((prop = grandchild->property ("sample-rate")) == 0) {
+                               continue;
+                       }
+                       state->sample_rate = atof (prop->value ());
+
+                       if ((prop = grandchild->property ("buffer-size")) == 0) {
+                               continue;
+                       }
+                       state->buffer_size = atoi (prop->value ());
+
+                       if ((prop = grandchild->property ("input-latency")) == 0) {
+                               continue;
+                       }
+                       state->input_latency = atoi (prop->value ());
+
+                       if ((prop = grandchild->property ("output-latency")) == 0) {
+                               continue;
+                       }
+                       state->output_latency = atoi (prop->value ());
+
+                       if ((prop = grandchild->property ("input-channels")) == 0) {
+                               continue;
+                       }
+                       state->input_channels = atoi (prop->value ());
+
+                       if ((prop = grandchild->property ("output-channels")) == 0) {
+                               continue;
+                       }
+                       state->output_channels = atoi (prop->value ());
+
+                       if ((prop = grandchild->property ("active")) == 0) {
+                               continue;
+                       }
+                       state->active = string_is_affirmative (prop->value ());
+
+                       if ((prop = grandchild->property ("midi-option")) == 0) {
+                               continue;
+                       }
+                       state->midi_option = prop->value ();
+
+                       state->midi_devices.clear();
+                       XMLNode* midinode;
+                       if ((midinode = ARDOUR::find_named_node (*grandchild, "MIDIDevices")) != 0) {
+                               const XMLNodeList mnc = midinode->children();
+                               for (XMLNodeList::const_iterator n = mnc.begin(); n != mnc.end(); ++n) {
+                                       if ((*n)->property (X_("name")) == 0
+                                                       || (*n)->property (X_("enabled")) == 0
+                                                       || (*n)->property (X_("input-latency")) == 0
+                                                       || (*n)->property (X_("output-latency")) == 0
+                                                ) {
+                                               continue;
+                                       }
+
+                                       MidiDeviceSettings ptr (new MidiDeviceSetting(
+                                                               (*n)->property (X_("name"))->value (),
+                                                               string_is_affirmative ((*n)->property (X_("enabled"))->value ()),
+                                                               atoi ((*n)->property (X_("input-latency"))->value ()),
+                                                               atoi ((*n)->property (X_("output-latency"))->value ())
+                                                               ));
+                                       state->midi_devices.push_back (ptr);
+                               }
+                       }
+
+#if 1
+                       /* remove accumulated duplicates (due to bug in ealier version)
+                        * this can be removed again before release
+                        */
+                       for (StateList::iterator i = states.begin(); i != states.end();) {
+                               if ((*i)->backend == state->backend &&
+                                               (*i)->driver == state->driver &&
+                                               (*i)->device == state->device) {
+                                       i =  states.erase(i);
+                               } else {
+                                       ++i;
+                               }
+                       }
 #endif
+
+                       states.push_back (state);
+               }
+       }
+
+       /* now see if there was an active state and switch the setup to it */
+
+       // purge states of backend that are not available in this built
+       vector<const ARDOUR::AudioBackendInfo*> backends = ARDOUR::AudioEngine::instance()->available_backends();
+       vector<std::string> backend_names;
+
+       for (vector<const ARDOUR::AudioBackendInfo*>::const_iterator i = backends.begin(); i != backends.end(); ++i) {
+               backend_names.push_back((*i)->name);
+       }
+       for (StateList::iterator i = states.begin(); i != states.end();) {
+               if (std::find(backend_names.begin(), backend_names.end(), (*i)->backend) == backend_names.end()) {
+                       i = states.erase(i);
+               } else {
+                       ++i;
+               }
+       }
+
+       for (StateList::const_iterator i = states.begin(); i != states.end(); ++i) {
+
+               if ((*i)->active) {
+                       set_current_state (*i);
+                       break;
+               }
+       }
 }
 
-int
-EngineControl::setup_engine (bool start)
-{
-       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
-       assert (backend);
+void
+EngineControl::set_current_state (const State& state)
+{
+       DEBUG_ECONTROL ("set_current_state");
+       PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+       backend_combo.set_active_text (state->backend);
+
+       /* The driver popdown strings need to be populated now so that
+        * set_active_text will actually set a valid entry. Then
+        * backend_changed() will populate all the other combo's so they
+        * can also be set to valid entries and the state will be restored
+        * correctly.
+        */
+       if (!state->driver.empty()) {
+               set_driver_popdown_strings ();
+       }
+       driver_combo.set_active_text (state->driver);
+       backend_changed ();
+
+       device_combo.set_active_text (state->device);
+       input_device_combo.set_active_text (state->input_device);
+       output_device_combo.set_active_text (state->output_device);
+       sample_rate_combo.set_active_text (rate_as_string (state->sample_rate));
+       set_active_text_if_present (buffer_size_combo, bufsize_as_string (state->buffer_size));
+       input_latency.set_value (state->input_latency);
+       output_latency.set_value (state->output_latency);
+       midi_option_combo.set_active_text (state->midi_option);
+}
+
+int
+EngineControl::push_state_to_backend (bool start)
+{
+       DEBUG_ECONTROL ("push_state_to_backend");
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+
+       if (!backend) {
+               return 0;
+       }
+
+       /* figure out what is going to change */
+
+       bool restart_required = false;
+       bool was_running = ARDOUR::AudioEngine::instance()->running();
+       bool change_driver = false;
+       bool change_device = false;
+       bool change_rate = false;
+       bool change_bufsize = false;
+       bool change_latency = false;
+       bool change_channels = false;
+       bool change_midi = false;
+
+       uint32_t ochan = get_output_channels ();
+       uint32_t ichan = get_input_channels ();
+
+       if (_have_control) {
+
+               if (started_at_least_once) {
+
+                       /* we can control the backend */
+
+                       if (backend->requires_driver_selection()) {
+                               if (get_driver() != backend->driver_name()) {
+                                       change_driver = true;
+                               }
+                       }
+
+                       if (backend->use_separate_input_and_output_devices()) {
+                               if (get_input_device_name() != backend->input_device_name()) {
+                                       change_device = true;
+                               }
+                               if (get_output_device_name() != backend->output_device_name()) {
+                                       change_device = true;
+                               }
+                       } else {
+                               if (get_device_name() != backend->device_name()) {
+                                       change_device = true;
+                               }
+                       }
+
+                       if (queue_device_changed) {
+                               change_device = true;
+                       }
+
+                       if (get_rate() != backend->sample_rate()) {
+                               change_rate = true;
+                       }
+
+                       if (get_buffer_size() != backend->buffer_size()) {
+                               change_bufsize = true;
+                       }
+
+                       if (get_midi_option() != backend->midi_option()) {
+                               change_midi = true;
+                       }
+
+                       /* zero-requested channels means "all available" */
+
+                       if (ichan == 0) {
+                               ichan = backend->input_channels();
+                       }
+
+                       if (ochan == 0) {
+                               ochan = backend->output_channels();
+                       }
+
+                       if (ichan != backend->input_channels()) {
+                               change_channels = true;
+                       }
+
+                       if (ochan != backend->output_channels()) {
+                               change_channels = true;
+                       }
+
+                       if (get_input_latency() != backend->systemic_input_latency() ||
+                                       get_output_latency() != backend->systemic_output_latency()) {
+                               change_latency = true;
+                       }
+               } else {
+                       /* backend never started, so we have to force a group
+                          of settings.
+                        */
+                       change_device = true;
+                       if (backend->requires_driver_selection()) {
+                               change_driver = true;
+                       }
+                       change_rate = true;
+                       change_bufsize = true;
+                       change_channels = true;
+                       change_latency = true;
+                       change_midi = true;
+               }
+
+       } else {
+
+               /* we have no control over the backend, meaning that we can
+                * only possibly change sample rate and buffer size.
+                */
+
+
+               if (get_rate() != backend->sample_rate()) {
+                       change_bufsize = true;
+               }
+
+               if (get_buffer_size() != backend->buffer_size()) {
+                       change_bufsize = true;
+               }
+       }
+
+       queue_device_changed = false;
+
+       if (!_have_control) {
+
+               /* We do not have control over the backend, so the best we can
+                * do is try to change the sample rate and/or bufsize and get
+                * out of here.
+                */
+
+               if (change_rate && !backend->can_change_sample_rate_when_running()) {
+                       return 1;
+               }
+
+               if (change_bufsize && !backend->can_change_buffer_size_when_running()) {
+                       return 1;
+               }
+
+               if (change_rate) {
+                       backend->set_sample_rate (get_rate());
+               }
+
+               if (change_bufsize) {
+                       backend->set_buffer_size (get_buffer_size());
+               }
+
+               if (start) {
+                       if (ARDOUR::AudioEngine::instance()->start ()) {
+                               error << string_compose (_("Could not start backend engine %1"), backend->name()) << endmsg;
+                               return -1;
+                       }
+               }
+
+               post_push ();
+
+               return 0;
+       }
+
+       /* determine if we need to stop the backend before changing parameters */
+
+       if (change_driver || change_device || change_channels || change_latency ||
+                       (change_rate && !backend->can_change_sample_rate_when_running()) ||
+                       change_midi ||
+                       (change_bufsize && !backend->can_change_buffer_size_when_running())) {
+               restart_required = true;
+       } else {
+               restart_required = false;
+       }
+
+       if (was_running) {
+
+               if (!change_driver && !change_device && !change_channels && !change_latency && !change_midi) {
+                       /* no changes in any parameters that absolutely require a
+                        * restart, so check those that might be changeable without a
+                        * restart
+                        */
+
+                       if (change_rate && !backend->can_change_sample_rate_when_running()) {
+                               /* can't do this while running ... */
+                               restart_required = true;
+                       }
 
-       /* grab the parameters from the GUI and apply them */
+                       if (change_bufsize && !backend->can_change_buffer_size_when_running()) {
+                               /* can't do this while running ... */
+                               restart_required = true;
+                       }
+               }
+       }
 
-       try {
-               if (backend->requires_driver_selection()) {
-                       if (backend->set_driver (get_driver())) {
+       if (was_running) {
+               if (restart_required) {
+                       if (ARDOUR_UI::instance()->disconnect_from_engine ()) {
                                return -1;
                        }
                }
+       }
+
 
-               if (backend->set_device_name (get_device_name())) {
+       if (change_driver && backend->set_driver (get_driver())) {
+               error << string_compose (_("Cannot set driver to %1"), get_driver()) << endmsg;
+               return -1;
+       }
+       if (backend->use_separate_input_and_output_devices()) {
+               if (change_device && backend->set_input_device_name (get_input_device_name())) {
+                       error << string_compose (_("Cannot set input device name to %1"), get_input_device_name()) << endmsg;
                        return -1;
                }
-
-               if (backend->set_sample_rate (get_rate())) {
-                       error << string_compose (_("Cannot set sample rate to %1"), get_rate()) << endmsg;
+               if (change_device && backend->set_output_device_name (get_output_device_name())) {
+                       error << string_compose (_("Cannot set output device name to %1"), get_output_device_name()) << endmsg;
                        return -1;
                }
-               if (backend->set_buffer_size (get_buffer_size())) {
-                       error << string_compose (_("Cannot set buffer size to %1"), get_buffer_size()) << endmsg;
+       } else {
+               if (change_device && backend->set_device_name (get_device_name())) {
+                       error << string_compose (_("Cannot set device name to %1"), get_device_name()) << endmsg;
                        return -1;
                }
+       }
+       if (change_rate && backend->set_sample_rate (get_rate())) {
+               error << string_compose (_("Cannot set sample rate to %1"), get_rate()) << endmsg;
+               return -1;
+       }
+       if (change_bufsize && backend->set_buffer_size (get_buffer_size())) {
+               error << string_compose (_("Cannot set buffer size to %1"), get_buffer_size()) << endmsg;
+               return -1;
+       }
+
+       if (change_channels || get_input_channels() == 0 || get_output_channels() == 0) {
                if (backend->set_input_channels (get_input_channels())) {
                        error << string_compose (_("Cannot set input channels to %1"), get_input_channels()) << endmsg;
                        return -1;
@@ -628,6 +2074,8 @@ EngineControl::setup_engine (bool start)
                        error << string_compose (_("Cannot set output channels to %1"), get_output_channels()) << endmsg;
                        return -1;
                }
+       }
+       if (change_latency) {
                if (backend->set_systemic_input_latency (get_input_latency())) {
                        error << string_compose (_("Cannot set input latency to %1"), get_input_latency()) << endmsg;
                        return -1;
@@ -636,32 +2084,92 @@ EngineControl::setup_engine (bool start)
                        error << string_compose (_("Cannot set output latency to %1"), get_output_latency()) << endmsg;
                        return -1;
                }
+       }
 
-               if (start) {
-                       return ARDOUR::AudioEngine::instance()->start();
+       if (change_midi) {
+               backend->set_midi_option (get_midi_option());
+       }
+
+       if (1 /* TODO */) {
+               for (vector<MidiDeviceSettings>::const_iterator p = _midi_devices.begin(); p != _midi_devices.end(); ++p) {
+                       if (_measure_midi) {
+                               if (*p == _measure_midi) {
+                                       backend->set_midi_device_enabled ((*p)->name, true);
+                               } else {
+                                       backend->set_midi_device_enabled ((*p)->name, false);
+                               }
+                               continue;
+                       }
+                       backend->set_midi_device_enabled ((*p)->name, (*p)->enabled);
+                       if (backend->can_set_systemic_midi_latencies()) {
+                               backend->set_systemic_midi_input_latency ((*p)->name, (*p)->input_latency);
+                               backend->set_systemic_midi_output_latency ((*p)->name, (*p)->output_latency);
+                       }
                }
+       }
 
-               return 0;
+       if (start || (was_running && restart_required)) {
+               if (ARDOUR_UI::instance()->reconnect_to_engine()) {
+                       return -1;
+               }
+       }
 
-       } catch (...) {
-               cerr << "exception thrown...\n";
-               return -1;
+       post_push ();
+
+       return 0;
+}
+
+void
+EngineControl::post_push ()
+{
+       /* get a pointer to the current state object, creating one if
+        * necessary
+        */
+
+       State state = get_saved_state_for_currently_displayed_backend_and_device ();
+
+       if (!state) {
+               state = save_state ();
+               assert (state);
+       } else {
+               store_state(state);
+       }
+
+       /* all off */
+
+       for (StateList::iterator i = states.begin(); i != states.end(); ++i) {
+               (*i)->active = false;
+       }
+
+       /* mark this one active (to be used next time the dialog is
+        * shown)
+        */
+
+       state->active = true;
+
+       if (_have_control) { // XXX
+               manage_control_app_sensitivity ();
        }
+
+       /* schedule a redisplay of MIDI ports */
+       //Glib::signal_timeout().connect (sigc::bind_return (sigc::mem_fun (*this, &EngineControl::refresh_midi_display), false), 1000);
 }
 
-uint32_t
+
+float
 EngineControl::get_rate () const
 {
-       double r = atof (sample_rate_combo.get_active_text ());
+       float r = atof (sample_rate_combo.get_active_text ());
        /* the string may have been translated with an abbreviation for
         * thousands, so use a crude heuristic to fix this.
         */
        if (r < 1000.0) {
                r *= 1000.0;
        }
-       return lrint (r);
+       return r;
 }
 
+
 uint32_t
 EngineControl::get_buffer_size () const
 {
@@ -669,21 +2177,39 @@ EngineControl::get_buffer_size () const
        uint32_t samples;
 
        if (sscanf (txt.c_str(), "%d", &samples) != 1) {
+               fprintf(stderr, "Find a trout and repeatedly slap the nearest C++ who throws exceptions without catching them.\n");
+               fprintf(stderr, "Ardour will likely crash now, giving you time to get the trout.\n");
                throw exception ();
        }
 
        return samples;
 }
 
+string
+EngineControl::get_midi_option () const
+{
+       return midi_option_combo.get_active_text();
+}
+
 uint32_t
 EngineControl::get_input_channels() const
 {
+       if (ARDOUR::Profile->get_mixbus()) {
+               boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+               if (!backend) return 0;
+               return backend->input_channels();
+       }
        return (uint32_t) input_channels_adjustment.get_value();
 }
 
 uint32_t
 EngineControl::get_output_channels() const
 {
+       if (ARDOUR::Profile->get_mixbus()) {
+               boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+               if (!backend) return 0;
+               return backend->input_channels();
+       }
        return (uint32_t) output_channels_adjustment.get_value();
 }
 
@@ -699,15 +2225,431 @@ EngineControl::get_output_latency() const
        return (uint32_t) output_latency_adjustment.get_value();
 }
 
+string
+EngineControl::get_backend () const
+{
+       return backend_combo.get_active_text ();
+}
+
 string
 EngineControl::get_driver () const
 {
-       return driver_combo.get_active_text ();
+       if (driver_combo.get_sensitive() && driver_combo.get_parent()) {
+               return driver_combo.get_active_text ();
+       } else {
+               return "";
+       }
 }
 
 string
 EngineControl::get_device_name () const
 {
-       return interface_combo.get_active_text ();
+       return device_combo.get_active_text ();
+}
+
+string
+EngineControl::get_input_device_name () const
+{
+       return input_device_combo.get_active_text ();
+}
+
+string
+EngineControl::get_output_device_name () const
+{
+       return output_device_combo.get_active_text ();
+}
+
+void
+EngineControl::control_app_button_clicked ()
+{
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+
+       if (!backend) {
+               return;
+       }
+
+       backend->launch_control_app ();
+}
+
+void
+EngineControl::manage_control_app_sensitivity ()
+{
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+
+       if (!backend) {
+               return;
+       }
+
+       string appname = backend->control_app_name();
+
+       if (appname.empty()) {
+               control_app_button.set_sensitive (false);
+       } else {
+               control_app_button.set_sensitive (true);
+       }
+}
+
+void
+EngineControl::set_desired_sample_rate (uint32_t sr)
+{
+       _desired_sample_rate = sr;
+       device_changed ();
+}
+
+void
+EngineControl::on_switch_page (GtkNotebookPage*, guint page_num)
+{
+       if (page_num == 0) {
+               cancel_button->set_sensitive (true);
+               ok_button->set_sensitive (true);
+               apply_button->set_sensitive (true);
+               _measure_midi.reset();
+       } else {
+               cancel_button->set_sensitive (false);
+               ok_button->set_sensitive (false);
+               apply_button->set_sensitive (false);
+       }
+
+       if (page_num == midi_tab) {
+               /* MIDI tab */
+               refresh_midi_display ();
+       }
+
+       if (page_num == latency_tab) {
+               /* latency tab */
+
+               if (ARDOUR::AudioEngine::instance()->running()) {
+                       // TODO - mark as 'stopped for latency
+                       ARDOUR_UI::instance()->disconnect_from_engine ();
+               }
+
+               {
+                       PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+
+                       /* save any existing latency values */
+
+                       uint32_t il = (uint32_t) input_latency.get_value ();
+                       uint32_t ol = (uint32_t) input_latency.get_value ();
+
+                       /* reset to zero so that our new test instance
+                          will be clean of any existing latency measures.
+
+                          NB. this should really be done by the backend
+                          when stated for latency measurement.
+                       */
+
+                       input_latency.set_value (0);
+                       output_latency.set_value (0);
+
+                       push_state_to_backend (false);
+
+                       /* reset control */
+
+                       input_latency.set_value (il);
+                       output_latency.set_value (ol);
+
+               }
+               // This should be done in push_state_to_backend()
+               if (ARDOUR::AudioEngine::instance()->prepare_for_latency_measurement()) {
+                       disable_latency_tab ();
+               }
+
+               enable_latency_tab ();
+
+       } else {
+               if (lm_running) {
+                       end_latency_detection ();
+                       ARDOUR::AudioEngine::instance()->stop_latency_detection();
+               }
+       }
+}
+
+/* latency measurement */
+
+bool
+EngineControl::check_audio_latency_measurement ()
+{
+       MTDM* mtdm = ARDOUR::AudioEngine::instance()->mtdm ();
+
+       if (mtdm->resolve () < 0) {
+               lm_results.set_markup (string_compose (results_markup, _("No signal detected ")));
+               return true;
+       }
+
+       if (mtdm->err () > 0.3) {
+               mtdm->invert ();
+               mtdm->resolve ();
+       }
+
+       char buf[256];
+       ARDOUR::framecnt_t const sample_rate = ARDOUR::AudioEngine::instance()->sample_rate();
+
+       if (sample_rate == 0) {
+               lm_results.set_markup (string_compose (results_markup, _("Disconnected from audio engine")));
+               ARDOUR::AudioEngine::instance()->stop_latency_detection ();
+               return false;
+       }
+
+       int frames_total = mtdm->del();
+       int extra = frames_total - ARDOUR::AudioEngine::instance()->latency_signal_delay();
+
+       snprintf (buf, sizeof (buf), "%s%d samples (%.3lf ms)\n%s%d samples (%.3lf ms)",
+                       _("Detected roundtrip latency: "),
+                       frames_total, frames_total * 1000.0f/sample_rate,
+                       _("Systemic latency: "),
+                       extra, extra * 1000.0f/sample_rate);
+
+       bool solid = true;
+
+       if (mtdm->err () > 0.2) {
+               strcat (buf, " ");
+               strcat (buf, _("(signal detection error)"));
+               solid = false;
+       }
+
+       if (mtdm->inv ()) {
+               strcat (buf, " ");
+               strcat (buf, _("(inverted - bad wiring)"));
+               solid = false;
+       }
+
+       lm_results.set_markup (string_compose (results_markup, buf));
+
+       if (solid) {
+               have_lm_results = true;
+               end_latency_detection ();
+               lm_use_button.set_sensitive (true);
+               return false;
+       }
+
+       return true;
+}
+
+bool
+EngineControl::check_midi_latency_measurement ()
+{
+       ARDOUR::MIDIDM* mididm = ARDOUR::AudioEngine::instance()->mididm ();
+
+       if (!mididm->have_signal () || mididm->latency () == 0) {
+               lm_results.set_markup (string_compose (results_markup, _("No signal detected ")));
+               return true;
+       }
+
+       char buf[256];
+       ARDOUR::framecnt_t const sample_rate = ARDOUR::AudioEngine::instance()->sample_rate();
+
+       if (sample_rate == 0) {
+               lm_results.set_markup (string_compose (results_markup, _("Disconnected from audio engine")));
+               ARDOUR::AudioEngine::instance()->stop_latency_detection ();
+               return false;
+       }
+
+       ARDOUR::framecnt_t frames_total = mididm->latency();
+       ARDOUR::framecnt_t extra = frames_total - ARDOUR::AudioEngine::instance()->latency_signal_delay();
+       snprintf (buf, sizeof (buf), "%s%" PRId64" samples (%.1lf ms) dev: %.2f[spl]\n%s%" PRId64" samples (%.1lf ms)",
+                       _("Detected roundtrip latency: "),
+                       frames_total, frames_total * 1000.0f / sample_rate, mididm->deviation (),
+                       _("Systemic latency: "),
+                       extra, extra * 1000.0f / sample_rate);
+
+       bool solid = true;
+
+       if (!mididm->ok ()) {
+               strcat (buf, " ");
+               strcat (buf, _("(averaging)"));
+               solid = false;
+       }
+
+       if (mididm->deviation () > 50.0) {
+               strcat (buf, " ");
+               strcat (buf, _("(too large jitter)"));
+               solid = false;
+       } else if (mididm->deviation () > 10.0) {
+               strcat (buf, " ");
+               strcat (buf, _("(large jitter)"));
+       }
+
+       if (solid) {
+               have_lm_results = true;
+               end_latency_detection ();
+               lm_use_button.set_sensitive (true);
+               lm_results.set_markup (string_compose (results_markup, buf));
+               return false;
+       } else if (mididm->processed () > 400) {
+               have_lm_results = false;
+               end_latency_detection ();
+               lm_results.set_markup (string_compose (results_markup, _("Timeout - large MIDI jitter.")));
+               return false;
+       }
+
+       lm_results.set_markup (string_compose (results_markup, buf));
+
+       return true;
+}
+
+void
+EngineControl::start_latency_detection ()
+{
+       ARDOUR::AudioEngine::instance()->set_latency_input_port (lm_input_channel_combo.get_active_text());
+       ARDOUR::AudioEngine::instance()->set_latency_output_port (lm_output_channel_combo.get_active_text());
+
+       if (ARDOUR::AudioEngine::instance()->start_latency_detection (_measure_midi ? true : false) == 0) {
+               lm_results.set_markup (string_compose (results_markup, _("Detecting ...")));
+               if (_measure_midi) {
+                       latency_timeout = Glib::signal_timeout().connect (mem_fun (*this, &EngineControl::check_midi_latency_measurement), 100);
+               } else {
+                       latency_timeout = Glib::signal_timeout().connect (mem_fun (*this, &EngineControl::check_audio_latency_measurement), 100);
+               }
+               lm_measure_label.set_text (_("Cancel"));
+               have_lm_results = false;
+               lm_use_button.set_sensitive (false);
+               lm_input_channel_combo.set_sensitive (false);
+               lm_output_channel_combo.set_sensitive (false);
+               lm_running = true;
+       }
+}
+
+void
+EngineControl::end_latency_detection ()
+{
+       latency_timeout.disconnect ();
+       ARDOUR::AudioEngine::instance()->stop_latency_detection ();
+       lm_measure_label.set_text (_("Measure"));
+       if (!have_lm_results) {
+               lm_use_button.set_sensitive (false);
+       }
+       lm_input_channel_combo.set_sensitive (true);
+       lm_output_channel_combo.set_sensitive (true);
+       lm_running = false;
+}
+
+void
+EngineControl::latency_button_clicked ()
+{
+       if (!lm_running) {
+               start_latency_detection ();
+       } else {
+               end_latency_detection ();
+       }
+}
+
+void
+EngineControl::use_latency_button_clicked ()
+{
+       if (_measure_midi) {
+               ARDOUR::MIDIDM* mididm = ARDOUR::AudioEngine::instance()->mididm ();
+               if (!mididm) {
+                       return;
+               }
+               ARDOUR::framecnt_t frames_total = mididm->latency();
+               ARDOUR::framecnt_t extra = frames_total - ARDOUR::AudioEngine::instance()->latency_signal_delay();
+               uint32_t one_way = max ((ARDOUR::framecnt_t) 0, extra / 2);
+               _measure_midi->input_latency = one_way;
+               _measure_midi->output_latency = one_way;
+               notebook.set_current_page (midi_tab);
+       } else {
+               MTDM* mtdm = ARDOUR::AudioEngine::instance()->mtdm ();
+
+               if (!mtdm) {
+                       return;
+               }
+
+               double one_way = rint ((mtdm->del() - ARDOUR::AudioEngine::instance()->latency_signal_delay()) / 2.0);
+               one_way = std::max (0., one_way);
+
+               input_latency_adjustment.set_value (one_way);
+               output_latency_adjustment.set_value (one_way);
+
+               /* back to settings page */
+               notebook.set_current_page (0);
+}
+       }
+
+
+bool
+EngineControl::on_delete_event (GdkEventAny* ev)
+{
+       if (notebook.get_current_page() == 2) {
+               /* currently on latency tab - be sure to clean up */
+               end_latency_detection ();
+       }
+       return ArdourDialog::on_delete_event (ev);
+}
+
+void
+EngineControl::engine_running ()
+{
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       assert (backend);
+
+       set_active_text_if_present (buffer_size_combo, bufsize_as_string (backend->buffer_size()));
+       sample_rate_combo.set_active_text (rate_as_string (backend->sample_rate()));
+
+       buffer_size_combo.set_sensitive (true);
+       sample_rate_combo.set_sensitive (true);
+
+       connect_disconnect_button.set_label (string_compose (_("Disconnect from %1"), backend->name()));
+       connect_disconnect_button.show();
+
+       started_at_least_once = true;
+       engine_status.set_markup(string_compose ("<span foreground=\"green\">%1</span>", _("Active")));
+}
+
+void
+EngineControl::engine_stopped ()
+{
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       assert (backend);
+
+       buffer_size_combo.set_sensitive (false);
+       connect_disconnect_button.set_label (string_compose (_("Connect to %1"), backend->name()));
+       connect_disconnect_button.show();
+
+       sample_rate_combo.set_sensitive (true);
+       buffer_size_combo.set_sensitive (true);
+       engine_status.set_markup(string_compose ("<span foreground=\"red\">%1</span>", _("Inactive")));
+}
+
+void
+EngineControl::device_list_changed ()
+{
+       PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1); // ??
+       list_devices ();
+       midi_option_changed();
+}
+
+void
+EngineControl::connect_disconnect_click()
+{
+       if (ARDOUR::AudioEngine::instance()->running()) {
+               ARDOUR_UI::instance()->disconnect_from_engine ();
+       } else {
+               ARDOUR_UI::instance()->reconnect_to_engine ();
+       }
+}
+
+void
+EngineControl::calibrate_audio_latency ()
+{
+       _measure_midi.reset ();
+       have_lm_results = false;
+       lm_use_button.set_sensitive (false);
+       lm_results.set_markup (string_compose (results_markup, _("No measurement results yet")));
+       notebook.set_current_page (latency_tab);
+}
+
+void
+EngineControl::calibrate_midi_latency (MidiDeviceSettings s)
+{
+       _measure_midi = s;
+       have_lm_results = false;
+       lm_use_button.set_sensitive (false);
+       lm_results.set_markup (string_compose (results_markup, _("No measurement results yet")));
+       notebook.set_current_page (latency_tab);
 }
 
+void
+EngineControl::configure_midi_devices ()
+{
+       notebook.set_current_page (midi_tab);
+}