missing initialization
[ardour.git] / gtk2_ardour / engine_dialog.cc
index ebdf60f4d64f1203ed104d777c57b0daee2d67ae..fa0ebe0240f2f1977602442056d7db4deed17188 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 <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/rc_configuration.h"
+#include "ardour/types.h"
 
 #include "pbd/convert.h"
 #include "pbd/error.h"
 
+#include "ardour_ui.h"
 #include "engine_dialog.h"
+#include "gui_thread.h"
 #include "i18n.h"
 
 using namespace std;
@@ -52,35 +57,40 @@ using namespace PBD;
 using namespace Glib;
 
 EngineControl::EngineControl ()
-       : input_latency_adjustment (0, 0, 99999, 1)
+       : ArdourDialog (_("Audio/MIDI Setup"))
+       , basic_packer (9, 3)
+       , 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
-       , _used (false)
+       , control_app_button (_("Device Control Panel"))
+       , lm_start_stop_label (_("Measure latency"))
+       , lm_use_button (_("Use results"))
+       , lm_table (5, 2)
+       , have_lm_results (false)
+       , midi_refresh_button (_("Refresh list"))
+       , aj_button (_("Start MIDI ALSA/JACK bridge"))
+       , ignore_changes (0)
+       , _desired_sample_rate (0)
+       , no_push (true)
+       , started_at_least_once (false)
 {
        using namespace Notebook_Helpers;
-       Label* label;
        vector<string> strings;
-       int row = 0;
-
-
-       /* basic parameters */
+       Label* label;
+       AttachOptions xopt = AttachOptions (FILL|EXPAND);
+       int row;
 
-       basic_packer.set_spacings (6);
+       set_name (X_("AudioMIDISetup"));
 
-       strings.clear ();
+       /* the backend combo is the one thing that is ALWAYS visible 
+        */
 
        vector<const ARDOUR::AudioBackendInfo*> backends = ARDOUR::AudioEngine::instance()->available_backends();
        for (vector<const ARDOUR::AudioBackendInfo*>::const_iterator b = backends.begin(); b != backends.end(); ++b) {
@@ -89,81 +99,107 @@ EngineControl::EngineControl ()
 
        set_popdown_strings (backend_combo, strings);
        backend_combo.set_active_text (strings.front());
-
        backend_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::backend_changed));
-       backend_changed ();
 
-       driver_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::driver_changed));
+       /* setup basic packing characteristics for the table used on the main
+        * tab of the notebook
+        */
 
-       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 ());
+       basic_packer.set_spacings (6);
+       basic_packer.set_border_width (12);
+       basic_packer.set_homogeneous (true);
+
+       /* pack it in */
+
+       basic_hbox.pack_start (basic_packer, false, false);
 
+       /* latency tab */
+
+       /* 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);
 
-       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, 2, 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++;
+       Gtk::Label* preamble;
 
-       label = manage (left_aligned_label (_("Device:")));
-       basic_packer.attach (*label, 0, 1, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
-       basic_packer.attach (device_combo, 1, 2, row, row + 1, FILL|EXPAND, (AttachOptions) 0);
-       row++;
+       preamble = manage (new Label);
+       preamble->set_width_chars (60);
+       preamble->set_line_wrap (true);
+       preamble->set_markup (_("<span weight=\"bold\">Turn down the volume on your hardware to a very low level.</span>"));
 
-       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);
+       lm_table.attach (*preamble, 0, 2, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
        row++;
 
-       sr_connection = sample_rate_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::sample_rate_changed));
+       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 or (less ideally) a speaker and microphone."));
 
-       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, 2, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
        row++;
 
-       bs_connection = buffer_size_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::buffer_size_changed));
+       label = manage (new Label (_("Output channel")));
+       lm_table.attach (*label, 0, 1, row, row+1, xopt, (AttachOptions) 0);
 
-       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);
+       Gtk::Alignment* misc_align = manage (new Alignment (0.0, 0.5));
+       misc_align->add (lm_output_channel_combo);
+       lm_table.attach (*misc_align, 1, 2, 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, 2, row, row+1, FILL, (AttachOptions) 0);
        ++row;
 
-       device_combo.set_size_request (250, -1);
-       input_device_combo.set_size_request (250, -1);
-       output_device_combo.set_size_request (250, -1);
+       xopt = AttachOptions(0);
 
-       device_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::device_changed));
+       lm_measure_button.add (lm_start_stop_label);
+       
+       lm_measure_button.signal_toggled().connect (sigc::mem_fun (*this, &EngineControl::latency_button_toggled));
+       lm_use_button.signal_clicked().connect (sigc::mem_fun (*this, &EngineControl::use_latency_button_clicked));
+       lm_use_button.set_sensitive (false);
+
+       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 latency\" button."));
+       lm_table.attach (*preamble, 0, 2, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
+       row++;
 
-       basic_hbox.pack_start (basic_packer, false, false);
+       lm_table.attach (lm_measure_button, 0, 2, row, row+1, xopt, (AttachOptions) 0);
+       ++row;
+       lm_table.attach (lm_results, 0, 2, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
+       ++row;
 
-       basic_packer.set_border_width (12);
-       midi_packer.set_border_width (12);
 
-       notebook.pages().push_back (TabElem (basic_hbox, _("Audio System Settings")));
-       notebook.pages().push_back (TabElem (midi_hbox, _("MIDI Settings")));
+       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, 2, row, row+1, AttachOptions(FILL|EXPAND), (AttachOptions) 0);
+       row++;
+
+       lm_table.attach (lm_use_button, 0, 2, row, row+1, xopt, (AttachOptions) 0);
+       ++row;
+
+       lm_results.set_markup ("<i>No measurement results yet</i>");
+
+       lm_vbox.set_border_width (12);
+       lm_vbox.pack_start (lm_table, false, false);
+
+       /* pack it all up */
+
+       notebook.pages().push_back (TabElem (basic_vbox, _("Audio")));
+       notebook.pages().push_back (TabElem (midi_vbox, _("MIDI")));
+       notebook.pages().push_back (TabElem (lm_vbox, _("Latency")));
        notebook.set_border_width (12);
 
        notebook.set_tab_pos (POS_RIGHT);
@@ -171,16 +207,243 @@ EngineControl::EngineControl ()
 
        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);
+
+       /* 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));
+
+       control_app_button.signal_clicked().connect (mem_fun (*this, &EngineControl::control_app_button_clicked));
+       manage_control_app_sensitivity ();
+
+       cancel_button = add_button (Gtk::Stock::CANCEL, Gtk::RESPONSE_CANCEL);
+       ok_button = add_button (Gtk::Stock::OK, Gtk::RESPONSE_OK);
+       apply_button = add_button (Gtk::Stock::APPLY, Gtk::RESPONSE_APPLY);
 
        /* Pick up any existing audio setup configuration, if appropriate */
 
        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());
+
+       backend_changed ();
+
        if (audio_setup) {
                set_state (*audio_setup);
        }
+
+       /* Connect to signals */
+
+       driver_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::driver_changed));
+       sample_rate_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::sample_rate_changed));
+       buffer_size_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::buffer_size_changed));
+       device_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::device_changed));
+
+       input_latency.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+       output_latency.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+       input_channels.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+       output_channels.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+
+       notebook.signal_switch_page().connect (sigc::mem_fun (*this, &EngineControl::on_switch_page));
+
+       no_push = false;
+}
+
+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:
+               push_state_to_backend (true);
+               hide ();
+               break;
+       case RESPONSE_DELETE_EVENT: {
+               GdkEventButton ev;
+               ev.type = GDK_BUTTON_PRESS;
+               ev.button = 1;
+               on_delete_event ((GdkEventAny*) &ev);
+               break;
+       }
+       default:
+               hide ();
+       }
+}
+
+void
+EngineControl::build_notebook ()
+{
+       Label* label;
+       AttachOptions xopt = AttachOptions (FILL|EXPAND);
+
+       /* clear the table */
+
+       Gtkmm2ext::container_clear (basic_vbox);
+       Gtkmm2ext::container_clear (basic_packer);
+
+       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);
+       
+       if (_have_control) {
+               build_full_control_notebook ();
+       } else {
+               build_no_control_notebook ();
+       }
+
+       basic_vbox.pack_start (basic_hbox, false, false);
+
+       if (_have_control) {
+               Gtk::HBox* hpacker = manage (new HBox);
+               hpacker->set_border_width (12);
+               hpacker->pack_start (control_app_button, false, false);
+               hpacker->show ();
+               control_app_button.show();
+               basic_vbox.pack_start (*hpacker);
+       }
+
+       basic_vbox.show_all ();
+}
+
+void
+EngineControl::build_full_control_notebook ()
+{
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       assert (backend);
+
+       using namespace Notebook_Helpers;
+       Label* label;
+       vector<string> strings;
+       AttachOptions xopt = AttachOptions (FILL|EXPAND);
+       int row = 1; // row zero == backend combo
+
+       /* start packing it up */
+
+       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++;
+       }
+
+       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++;
+
+       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, xopt, (AttachOptions) 0);
+       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);
+
+       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);
+
+       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;
+
+       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, xopt, (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, xopt, (AttachOptions) 0);
+       ++row;
+
+}
+
+void
+EngineControl::build_no_control_notebook ()
+{
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       assert (backend);
+
+       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 (_("The %1 audio backend was configured and started externally.\nThis limits your control over it."), backend->name());
+
+       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++;
+
+       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++;
+       }
+
+       connect_disconnect_button.signal_clicked().connect (sigc::mem_fun (*this, &EngineControl::connect_disconnect_click));
+
+       basic_packer.attach (connect_disconnect_button, 0, 2, row, row+1, FILL, AttachOptions (0));
+       row++;
 }
 
 EngineControl::~EngineControl ()
@@ -188,29 +451,174 @@ EngineControl::~EngineControl ()
 
 }
 
+void
+EngineControl::disable_latency_tab ()
+{
+       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);
+}
+
+void
+EngineControl::enable_latency_tab ()
+{
+       vector<string> outputs;
+       ARDOUR::AudioEngine::instance()->get_physical_outputs (ARDOUR::DataType::AUDIO, outputs);
+       set_popdown_strings (lm_output_channel_combo, outputs);
+       lm_output_channel_combo.set_active_text (outputs.front());
+
+       vector<string> inputs;
+       ARDOUR::AudioEngine::instance()->get_physical_inputs (ARDOUR::DataType::AUDIO, inputs);
+       set_popdown_strings (lm_input_channel_combo, inputs);
+       lm_input_channel_combo.set_active_text (inputs.front());
+
+       lm_measure_button.set_sensitive (true);
+}
+
+void
+EngineControl::setup_midi_tab_for_backend ()
+{
+       string backend = backend_combo.get_active_text ();
+
+       Gtkmm2ext::container_clear (midi_vbox);
+
+       midi_vbox.set_border_width (12);
+       midi_device_table.set_border_width (12);
+
+       if (backend == "JACK") {
+               setup_midi_tab_for_jack ();
+       }
+
+       midi_vbox.pack_start (midi_device_table, true, true);
+       midi_vbox.pack_start (midi_refresh_button, false, false);
+       midi_vbox.show_all ();
+
+       midi_refresh_button.signal_clicked().connect (sigc::mem_fun (*this, &EngineControl::refresh_midi_display));
+}
+
+void
+EngineControl::setup_midi_tab_for_jack ()
+{
+       midi_vbox.pack_start (aj_button, false, false);
+}      
+
+void
+EngineControl::refresh_midi_display ()
+{
+       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
+       assert (backend);
+
+       vector<string> midi_inputs;
+       vector<string> midi_outputs;
+       int row  = 0;
+       AttachOptions xopt = AttachOptions (FILL|EXPAND);
+       Gtk::Label* l;
+
+       Gtkmm2ext::container_clear (midi_device_table);
+
+       backend->get_physical_inputs (ARDOUR::DataType::MIDI, midi_inputs);
+       backend->get_physical_outputs (ARDOUR::DataType::MIDI, midi_outputs);
+
+       midi_device_table.set_spacings (6);
+       midi_device_table.set_homogeneous (true);
+       midi_device_table.resize (midi_inputs.size() + midi_outputs.size() + 3, 1);
+
+       l = manage (new Label);
+       l->set_markup (string_compose ("<span size=\"large\" weight=\"bold\">%1</span>", _("MIDI Inputs")));
+       midi_device_table.attach (*l, 0, 1, row, row + 1, xopt, AttachOptions (0));
+       l->set_alignment (0, 0.5);
+       row++;
+       l->show ();
+       
+       for (vector<string>::iterator p = midi_inputs.begin(); p != midi_inputs.end(); ++p) {
+               l = manage (new Label ((*p).substr ((*p).find_last_of (':') + 1)));
+               l->set_alignment (0, 0.5);
+               midi_device_table.attach (*l, 0, 1, row, row + 1, xopt, AttachOptions (0));
+               l->show ();
+               row++;
+       }
+
+       row++; // extra row of spacing
+
+       l = manage (new Label);
+       l->set_markup (string_compose ("<span size=\"large\" weight=\"bold\">%1</span>", _("MIDI Outputs")));
+       midi_device_table.attach (*l, 0, 1, row, row + 1, xopt, AttachOptions (0));
+       l->set_alignment (0, 0.5);
+       row++;
+       l->show ();
+
+       for (vector<string>::iterator p = midi_outputs.begin(); p != midi_outputs.end(); ++p) {
+               l = manage (new Label ((*p).substr ((*p).find_last_of (':') + 1)));
+               l->set_alignment (0, 0.5);
+               midi_device_table.attach (*l, 0, 1, row, row + 1, xopt, AttachOptions (0));
+               l->show ();
+               row++;
+       }
+}
+
+void
+EngineControl::update_sensitivity ()
+{
+}
+
 void
 EngineControl::backend_changed ()
 {
+       if (ignore_changes) {
+               return;
+       }
+
        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? */
+               /* eh? setting the backend failed... how ? */
                return;
        }
 
+       _have_control = ARDOUR::AudioEngine::instance()->setup_required ();
+
+       build_notebook ();
+       setup_midi_tab_for_backend ();
+
        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 ();
+               
+               if (!drivers.empty()) {
+                       {
+                               PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+                               set_popdown_strings (driver_combo, drivers);
+                               driver_combo.set_active_text (drivers.front());
+                       }
+
+                       driver_changed ();
+               }
+               
        } 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 ();
        }
        
-       maybe_set_state ();
+       maybe_display_saved_state ();
+}
+
+bool
+EngineControl::print_channel_count (Gtk::SpinButton* sb)
+{
+       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;
 }
 
 void
@@ -238,76 +646,194 @@ EngineControl::list_devices ()
                available_devices.push_back (i->name);
        }
 
-       set_popdown_strings (device_combo, available_devices);
-       set_popdown_strings (input_device_combo, available_devices);
-       set_popdown_strings (output_device_combo, available_devices);
-       
        if (!available_devices.empty()) {
-               device_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());
-       }
 
-       device_changed ();
+               update_sensitivity ();
+                                               
+               {
+                       PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
+                       set_popdown_strings (device_combo, available_devices);
+                       device_combo.set_active_text (available_devices.front());
+               }
+
+               device_changed ();
+
+               ok_button->set_sensitive (true);
+               apply_button->set_sensitive (true);
+
+       } else {
+               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);
+               ok_button->set_sensitive (false);
+               apply_button->set_sensitive (false);
+       }
 }
-       
+
 void
 EngineControl::driver_changed ()
 {
+       if (ignore_changes) {
+               return;
+       }
+
        boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
        assert (backend);
 
        backend->set_driver (driver_combo.get_active_text());
        list_devices ();
 
-       maybe_set_state ();
+       maybe_display_saved_state ();
 }
 
 void
 EngineControl::device_changed ()
 {
+       if (ignore_changes) {
+               return;
+       }
+
        boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
        assert (backend);
        string device_name = device_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 ();
+       {
+               PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
 
-       /* sample rates */
+               /* don't allow programmatic change to combos to cause a
+                  recursive call to this method.
+               */
+               
+               /* sample rates */
+               
+               string desired;
+               
+               vector<float> sr;
 
-       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);
+               if (_have_control) {
+                       sr = backend->available_sample_rates (device_name);
                } else {
-                       snprintf (buf, sizeof (buf), "%.0f kHz", (*x)/1000.0);
+
+                       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);
                }
-               s.push_back (buf);
+
+               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 (s.front());
+                       } else {
+                               sample_rate_combo.set_active_text (desired);
+                       }
+
+               } else {
+                       sample_rate_combo.set_sensitive (false);
+               }
+
+               /* buffer sizes */
+               
+               vector<uint32_t> bs;
+               
+               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());
+                       show_buffer_duration ();
+               } else {
+                       buffer_size_combo.set_sensitive (false);
+               }
+
+               /* XXX theoretically need to set min + max channel counts here
+                */
+               
+               manage_control_app_sensitivity ();
        }
 
-       set_popdown_strings (sample_rate_combo, s);
-       sample_rate_combo.set_active_text (s.front());
+       /* pick up any saved state for this device */
 
-       reshow_buffer_sizes (true);
+       maybe_display_saved_state ();
 
-       sr_connection.unblock ();
-       
-       maybe_set_state ();
+       /* and push it to the backend */
+
+       push_state_to_backend (false);
 }      
 
+string
+EngineControl::rate_as_string (float r)
+{
+       char buf[32];
+       if (fmod (r, 1000.0f)) {
+               snprintf (buf, sizeof (buf), "%.1f kHz", r/1000.0);
+       } else {
+               snprintf (buf, sizeof (buf), "%.0f kHz", r/1000.0);
+       }
+       return buf;
+}
+
+string
+EngineControl::bufsize_as_string (uint32_t sz)
+{
+       /* Translators: "samples" is always plural here, so no
+          need for plural+singular forms.
+       */
+       char buf[32];
+       snprintf (buf, sizeof (buf), _("%u samples"), sz);
+       return buf;
+}
+
 void 
 EngineControl::sample_rate_changed ()
 {
+       if (ignore_changes) {
+               return;
+       }
+
        /* reset the strings for buffer size to show the correct msec value
-          (reflecting the new sample rate
+          (reflecting the new sample rate).
        */
 
-       reshow_buffer_sizes (false);
+       show_buffer_duration ();
        save_state ();
 
 }
@@ -315,80 +841,43 @@ EngineControl::sample_rate_changed ()
 void 
 EngineControl::buffer_size_changed ()
 {
+       if (ignore_changes) {
+               return;
+       }
+
+       show_buffer_duration ();
        save_state ();
 }
 
 void
-EngineControl::reshow_buffer_sizes (bool size_choice_changed)
+EngineControl::show_buffer_duration ()
 {
-       boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
-       assert (backend);
-       string device_name = device_combo.get_active_text ();
-       vector<string> s;
-       uint32_t existing_size_choice = 0;
-       string new_target_string;
 
        /* buffer sizes  - convert from just samples to samples + msecs for
         * the displayed string
         */
 
-       bs_connection.block ();
-
-       if (!size_choice_changed) {
-               sscanf (buffer_size_combo.get_active_text().c_str(), "%" PRIu32, &existing_size_choice);
-       }
-
-       s.clear ();
-       vector<uint32_t> bs = backend->available_buffer_sizes(device_name);
+       string bs_text = buffer_size_combo.get_active_text ();
+       uint32_t samples = atoi (bs_text); /* will ignore trailing text */
        uint32_t rate = get_rate();
 
-       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 this is the size previously chosen, this is the string we
-                * will want to be active in the combo.
-                */
-
-               if (existing_size_choice == *x) {
-                       new_target_string = buf;
-               }
-                       
-       }
-
-       set_popdown_strings (buffer_size_combo, s);
-
-       if (!new_target_string.empty()) {
-               buffer_size_combo.set_active_text (new_target_string);
-       } else {
-               buffer_size_combo.set_active_text (s.front());
-       }
-
-       bs_connection.unblock ();
+       /* Translators: "msecs" is ALWAYS plural here, so we do not
+          need singular form as well.
+       */
+       /* 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.
+       */
+       char buf[32];
+       snprintf (buf, sizeof (buf), _("(%.1f msecs)"), (2 * samples) / (rate/1000.0));
+       buffer_size_duration_label.set_text (buf);
 }
 
 void
-EngineControl::audio_mode_changed ()
+EngineControl::parameter_changed ()
 {
-       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);
+       if (!ignore_changes) {
+               save_state ();
        }
 }
 
@@ -408,14 +897,14 @@ EngineControl::get_matching_state (const string& backend,
 }
 
 EngineControl::State*
-EngineControl::get_current_state ()
+EngineControl::get_saved_state_for_currently_displayed_backend_and_device ()
 {
        boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
 
        if (backend) {
                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());
+                                          (backend->requires_driver_selection() ? (std::string) driver_combo.get_active_text() : string()),
+                                          device_combo.get_active_text());
        }
 
 
@@ -424,44 +913,66 @@ EngineControl::get_current_state ()
                                   device_combo.get_active_text());
 }
 
-void
+EngineControl::State*
 EngineControl::save_state ()
 {
+       if (!_have_control) {
+               return 0;
+       }
+
        bool existing = true;
-       State* state = get_current_state ();
+       State* state = get_saved_state_for_currently_displayed_backend_and_device ();
 
        if (!state) {
                existing = false;
                state = new State;
        }
        
-       state->backend = backend_combo.get_active_text ();
-       state->driver = driver_combo.get_active_text ();
-       state->device = device_combo.get_active_text ();
-       state->buffer_size = buffer_size_combo.get_active_text ();
-       state->sample_rate = sample_rate_combo.get_active_text ();
+       store_state (*state);
 
        if (!existing) {
                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.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 ();
 }
 
 void
-EngineControl::maybe_set_state ()
+EngineControl::maybe_display_saved_state ()
 {
-       State* state = get_current_state ();
+       if (!_have_control) {
+               return;
+       }
+
+       State* state = get_saved_state_for_currently_displayed_backend_and_device ();
 
        if (state) {
-               sr_connection.block ();
-               bs_connection.block ();
-               sample_rate_combo.set_active_text (state->sample_rate);
-               /* need to reset possible strings for buffer size before we do
-                  this
+               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));
+               }
+               buffer_size_combo.set_active_text (bufsize_as_string (state->buffer_size));
+               /* call this explicitly because we're ignoring changes to
+                  the controls at this point.
                */
-               reshow_buffer_sizes (false);
-               buffer_size_combo.set_active_text (state->buffer_size);
-               bs_connection.unblock ();
-               sr_connection.unblock ();
+               show_buffer_duration ();
+               input_latency.set_value (state->input_latency);
+               output_latency.set_value (state->output_latency);
        }
 }
        
@@ -471,30 +982,28 @@ EngineControl::get_state ()
        XMLNode* root = new XMLNode ("AudioMIDISetup");
        std::string path;
 
-       if (_used) {
-
-               if (!states.empty()) {
-                       XMLNode* state_nodes = new XMLNode ("EngineStates");
+       if (!states.empty()) {
+               XMLNode* state_nodes = new XMLNode ("EngineStates");
+               
+               for (StateList::const_iterator i = states.begin(); i != states.end(); ++i) {
                        
-                       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 ("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);
-                                       
-                               state_nodes->add_child_nocopy (*node);
-                       }
-
-                       root->add_child_nocopy (*state_nodes);
+                       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 ("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");
+                       
+                       state_nodes->add_child_nocopy (*node);
                }
+               
+               root->add_child_nocopy (*state_nodes);
        }
 
        return *root;
@@ -554,65 +1063,248 @@ EngineControl::set_state (const XMLNode& root)
                        if ((prop = grandchild->property ("sample-rate")) == 0) {
                                continue;
                        }
-                       state.sample_rate = prop->value ();
+                       state.sample_rate = atof (prop->value ());
                        
                        if ((prop = grandchild->property ("buffer-size")) == 0) {
                                continue;
                        }
-                       state.buffer_size = prop->value ();
+                       state.buffer_size = atoi (prop->value ());
                        
                        if ((prop = grandchild->property ("input-latency")) == 0) {
                                continue;
                        }
-                       state.input_latency = prop->value ();
+                       state.input_latency = atoi (prop->value ());
                        
                        if ((prop = grandchild->property ("output-latency")) == 0) {
                                continue;
                        }
-                       state.output_latency = prop->value ();
+                       state.output_latency = atoi (prop->value ());
                        
                        if ((prop = grandchild->property ("input-channels")) == 0) {
                                continue;
                        }
-                       state.input_channels = prop->value ();
+                       state.input_channels = atoi (prop->value ());
                        
                        if ((prop = grandchild->property ("output-channels")) == 0) {
                                continue;
                        }
-                       state.output_channels = prop->value ();
+                       state.output_channels = atoi (prop->value ());
+
+                       if ((prop = grandchild->property ("active")) == 0) {
+                               continue;
+                       }
+                       state.active = string_is_affirmative (prop->value ());
                        
                        states.push_back (state);
                }
        }
+
+       /* now see if there was an active state and switch the setup to it */
+       
+       for (StateList::const_iterator i = states.begin(); i != states.end(); ++i) {
+
+               if ((*i).active) {
+                       ignore_changes++;
+                       backend_combo.set_active_text ((*i).backend);
+                       driver_combo.set_active_text ((*i).driver);
+                       device_combo.set_active_text ((*i).device);
+                       sample_rate_combo.set_active_text (rate_as_string ((*i).sample_rate));
+                       buffer_size_combo.set_active_text (bufsize_as_string ((*i).buffer_size));
+                       input_latency.set_value ((*i).input_latency);
+                       output_latency.set_value ((*i).output_latency);
+                       ignore_changes--;
+                       break;
+               }
+       }
 }
 
+
 int
-EngineControl::setup_engine (bool start)
+EngineControl::push_state_to_backend (bool start)
 {
+       if (no_push) {
+               return 0;
+       }
+
        boost::shared_ptr<ARDOUR::AudioBackend> backend = ARDOUR::AudioEngine::instance()->current_backend();
-       assert (backend);
 
-       /* grab the parameters from the GUI and apply them */
+       if (!backend) {
+               return 0;
+       }
+       
+       /* figure out what is going to change */
 
-       try {
-               if (backend->requires_driver_selection()) {
-                       if (backend->set_driver (get_driver())) {
-                               return -1;
+       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;
+
+       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 (get_device_name() != backend->device_name()) {
+                               change_device = true;
+                       }
+                       
+                       if (get_rate() != backend->sample_rate()) {
+                               change_rate = true;
+                       }
+                       
+                       if (get_buffer_size() != backend->buffer_size()) {
+                               change_bufsize = 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_driver = true;
+                       change_device = true;
+                       change_rate = true;
+                       change_bufsize = true;
+                       change_channels = true;
+                       change_latency = true;
                }
 
-               if (backend->set_device_name (get_device_name())) {
-                       return -1;
+       } 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 (backend->set_sample_rate (get_rate())) {
-                       error << string_compose (_("Cannot set sample rate to %1"), get_rate()) << endmsg;
-                       return -1;
+               if (get_buffer_size() != backend->buffer_size()) {
+                       change_bufsize = true;
                }
-               if (backend->set_buffer_size (get_buffer_size())) {
-                       error << string_compose (_("Cannot set buffer size to %1"), get_buffer_size()) << endmsg;
-                       return -1;
+       }
+
+       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());
+               }
+
+               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_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) {
+                       /* 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;
+                       }
+
+                       if (change_bufsize && !backend->can_change_buffer_size_when_running()) {
+                               /* can't do this while running ... */
+                               restart_required = true;
+                       }
+               }
+       }
+
+       if (was_running) {
+               if (restart_required) {
+                       if (ARDOUR_UI::instance()->disconnect_from_engine ()) {
+                               return -1;
+                       }
                }
+       }
+               
+
+       if (change_driver && backend->set_driver (get_driver())) {
+               error << string_compose (_("Cannot set driver to %1"), get_driver()) << endmsg;
+               return -1;
+       }
+       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;
@@ -621,6 +1313,8 @@ 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;
@@ -629,38 +1323,68 @@ EngineControl::setup_engine (bool start)
                        error << string_compose (_("Cannot set output latency to %1"), get_output_latency()) << endmsg;
                        return -1;
                }
-
-               /* we've used this dialog to configure the engine, which means
-                * that our state becomes relevant for saving (and thus
-                * implicitly, restoring.
-                */
-
-               _used = true;
-
-               if (start) {
-                       return ARDOUR::AudioEngine::instance()->start();
+       }
+                       
+       if (start || (was_running && restart_required)) {
+               if (ARDOUR_UI::instance()->reconnect_to_engine()) {
+                       return -1;
                }
+       }
+       
+       post_push ();
 
-               return 0;
+       return 0;
+}
 
-       } catch (...) {
-               cerr << "exception thrown...\n";
-               return -1;
+void
+EngineControl::post_push ()
+{
+       /* get a pointer to the current state object, creating one if
+        * necessary
+        */
+       
+       if (_have_control) {
+               State* state = get_saved_state_for_currently_displayed_backend_and_device ();
+               
+               if (!state) {
+                       state = save_state ();
+                       assert (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;
+               
+               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
@@ -699,6 +1423,12 @@ 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
 {
@@ -711,3 +1441,262 @@ EngineControl::get_device_name () const
        return 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);
+       } else {
+               cancel_button->set_sensitive (false);
+               ok_button->set_sensitive (false);
+               apply_button->set_sensitive (false);
+       }
+
+       if (page_num == 1) {
+               /* MIDI tab */
+               refresh_midi_display ();
+       }
+
+       if (page_num == 2) {
+               /* latency tab */
+
+               if (!ARDOUR::AudioEngine::instance()->running()) {
+                       
+                       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 of JACK
+                          will be clean of any existing latency measures.
+                       */
+                       
+                       input_latency.set_value (0);
+                       output_latency.set_value (0);
+                       
+                       /* reset control */
+
+                       input_latency.set_value (il);
+                       output_latency.set_value (ol);
+
+               } 
+
+               if (ARDOUR::AudioEngine::instance()->prepare_for_latency_measurement()) {
+                       disable_latency_tab ();
+               }
+
+               enable_latency_tab ();
+
+       } else {
+               ARDOUR::AudioEngine::instance()->stop_latency_detection();
+       }
+}
+
+/* latency measurement */
+
+bool
+EngineControl::check_latency_measurement ()
+{
+        MTDM* mtdm = ARDOUR::AudioEngine::instance()->mtdm ();
+
+        if (mtdm->resolve () < 0) {
+               lm_results.set_markup (string_compose ("<span foreground=\"red\">%1</span>", _("No signal detected ")));
+                return true;
+        }
+
+        if (mtdm->err () > 0.3) {
+                mtdm->invert ();
+                mtdm->resolve ();
+        }
+
+        char buf[128];
+       ARDOUR::framecnt_t const sample_rate = ARDOUR::AudioEngine::instance()->sample_rate();
+
+        if (sample_rate == 0) {
+                lm_results.set_text (_("Disconnected from audio engine"));
+               ARDOUR::AudioEngine::instance()->stop_latency_detection ();
+                return false;
+        }
+
+       uint32_t frames_total = mtdm->del();
+       uint32_t extra = frames_total - ARDOUR::AudioEngine::instance()->latency_signal_delay();
+
+        snprintf (buf, sizeof (buf), "%u samples %10.3lf ms", extra, extra * 1000.0f/sample_rate);
+
+        bool solid = true;
+
+        if (mtdm->err () > 0.2) {
+                strcat (buf, " ??");
+                solid = false;
+        }
+
+        if (mtdm->inv ()) {
+                strcat (buf, " (Inv)");
+                solid = false;
+        }
+
+        if (solid) {
+                lm_measure_button.set_active (false);
+               lm_use_button.set_sensitive (true);
+                strcat (buf, " (set)");
+               have_lm_results = true;
+        }
+       
+        lm_results.set_text (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());
+       ARDOUR::AudioEngine::instance()->start_latency_detection ();
+       lm_results.set_text (_("Detecting ..."));
+       latency_timeout = Glib::signal_timeout().connect (mem_fun (*this, &EngineControl::check_latency_measurement), 250);
+       lm_start_stop_label.set_text (_("Cancel measurement"));
+       have_lm_results = false;
+       lm_input_channel_combo.set_sensitive (false);
+       lm_output_channel_combo.set_sensitive (false);
+}
+
+void
+EngineControl::end_latency_detection ()
+{
+       ARDOUR::AudioEngine::instance()->stop_latency_detection ();
+       latency_timeout.disconnect ();
+       lm_start_stop_label.set_text (_("Measure latency"));
+       if (!have_lm_results) {
+               lm_results.set_markup ("<i>No measurement results yet</i>");
+       }
+       lm_input_channel_combo.set_sensitive (true);
+       lm_output_channel_combo.set_sensitive (true);
+}
+
+void
+EngineControl::latency_button_toggled ()
+{
+        if (lm_measure_button.get_active ()) {
+               start_latency_detection ();
+       } else {
+               end_latency_detection ();
+        }
+}
+
+void
+EngineControl::use_latency_button_clicked ()
+{
+        MTDM* mtdm = ARDOUR::AudioEngine::instance()->mtdm ();
+
+       if (!mtdm) {
+               return;
+       }
+
+       uint32_t frames_total = mtdm->del();
+       uint32_t extra = frames_total - ARDOUR::AudioEngine::instance()->latency_signal_delay();
+       uint32_t one_way = extra/2;
+
+       input_latency_adjustment.set_value (one_way);
+       output_latency_adjustment.set_value (one_way);
+}
+
+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);
+
+       buffer_size_combo.set_active_text (bufsize_as_string (backend->buffer_size()));
+       sample_rate_combo.set_active_text (rate_as_string (backend->sample_rate()));
+
+       if (backend->can_change_buffer_size_when_running()) {
+               buffer_size_combo.set_sensitive (true);
+       } else {
+               buffer_size_combo.set_sensitive (false);
+       }
+
+       if (backend->can_change_sample_rate_when_running()) {
+               sample_rate_combo.set_sensitive (true);
+       } else {
+               sample_rate_combo.set_sensitive (false);
+       }
+
+       connect_disconnect_button.set_label (string_compose (_("Disconnect from %1"), backend->name()));
+
+       started_at_least_once = true;
+}
+
+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()));
+
+       sample_rate_combo.set_sensitive (true);
+       buffer_size_combo.set_sensitive (true);
+}
+       
+void
+EngineControl::connect_disconnect_click() 
+{
+       if (ARDOUR::AudioEngine::instance()->running()) {
+               ARDOUR_UI::instance()->disconnect_from_engine ();
+       } else {
+               ARDOUR_UI::instance()->reconnect_to_engine ();
+       }
+}