ALSA Backend: align midi output buffer with n_periods (currently 2)

diff --git a/libs/backends/alsa/alsa_audiobackend.cc b/libs/backends/alsa/alsa_audiobackend.cc
index c5382e81d81adae432bf862d12c30c6e529b1c3d..7c4288cedb9cd4a3bea4522cf7ac5ec0d32317c1 100644 (file)
--- a/libs/backends/alsa/alsa_audiobackend.cc
+++ b/libs/backends/alsa/alsa_audiobackend.cc
@@ -470,6 +470,8 @@ AlsaAudioBackend::_start (bool for_latency_measurement)
        if (for_latency_measurement) {
                _systemic_audio_input_latency = 0;
                _systemic_audio_output_latency = 0;
+               _systemic_midi_input_latency = 0;
+               _systemic_midi_output_latency = 0;
        }
 
        register_system_midi_ports();
@@ -528,7 +530,7 @@ int
 AlsaAudioBackend::stop ()
 {
        void *status;
-       if (!_active) {
+       if (!_run) {
                return 0;
        }
 
@@ -1351,14 +1353,19 @@ AlsaAudioBackend::main_process_thread ()
                                        return 0;
                                }
 
+                               i = 0;
+                               for (std::vector<AlsaPort*>::iterator it = _system_midi_out.begin (); it != _system_midi_out.end (); ++it, ++i) {
+                                       static_cast<AlsaMidiPort*>(*it)->next_period();
+                               }
+
                                /* queue midi*/
                                i = 0;
                                for (std::vector<AlsaPort*>::const_iterator it = _system_midi_out.begin (); it != _system_midi_out.end (); ++it, ++i) {
                                        assert (_rmidi_out.size() > i);
+                                       const AlsaMidiBuffer src = static_cast<const AlsaMidiPort*>(*it)->const_buffer();
                                        AlsaRawMidiOut *rm = static_cast<AlsaRawMidiOut*>(_rmidi_out.at(i));
-                                       const AlsaMidiBuffer *src = static_cast<const AlsaMidiBuffer*>((*it)->get_buffer(0));
-                                       rm->sync_time (clock1); // ?? use clock pre DSP load?
-                                       for (AlsaMidiBuffer::const_iterator mit = src->begin (); mit != src->end (); ++mit) {
+                                       rm->sync_time (clock1);
+                                       for (AlsaMidiBuffer::const_iterator mit = src.begin (); mit != src.end (); ++mit) {
                                                rm->send_event ((*mit)->timestamp(), (*mit)->data(), (*mit)->size());
                                        }
                                }
@@ -1656,8 +1663,10 @@ void* AlsaAudioPort::get_buffer (pframes_t n_samples)
 
 AlsaMidiPort::AlsaMidiPort (AlsaAudioBackend &b, const std::string& name, PortFlags flags)
        : AlsaPort (b, name, flags)
+       , _bufperiod (0)
 {
-       _buffer.clear ();
+       _buffer[0].clear ();
+       _buffer[1].clear ();
 }
 
 AlsaMidiPort::~AlsaMidiPort () { }
@@ -1671,18 +1680,18 @@ struct MidiEventSorter {
 void* AlsaMidiPort::get_buffer (pframes_t /* nframes */)
 {
        if (is_input ()) {
-               _buffer.clear ();
+               (_buffer[_bufperiod]).clear ();
                for (std::vector<AlsaPort*>::const_iterator i = get_connections ().begin ();
                                i != get_connections ().end ();
                                ++i) {
                        const AlsaMidiBuffer src = static_cast<const AlsaMidiPort*>(*i)->const_buffer ();
                        for (AlsaMidiBuffer::const_iterator it = src.begin (); it != src.end (); ++it) {
-                               _buffer.push_back (boost::shared_ptr<AlsaMidiEvent>(new AlsaMidiEvent (**it)));
+                               (_buffer[_bufperiod]).push_back (boost::shared_ptr<AlsaMidiEvent>(new AlsaMidiEvent (**it)));
                        }
                }
-               std::sort (_buffer.begin (), _buffer.end (), MidiEventSorter());
+               std::sort ((_buffer[_bufperiod]).begin (), (_buffer[_bufperiod]).end (), MidiEventSorter());
        }
-       return &_buffer;
+       return &(_buffer[_bufperiod]);
 }
 
 AlsaMidiEvent::AlsaMidiEvent (const pframes_t timestamp, const uint8_t* data, size_t size)

diff --git a/libs/backends/alsa/alsa_audiobackend.h b/libs/backends/alsa/alsa_audiobackend.h
index 98d3aaa13f9261e3e4ad6542817a889027aae9e8..1f6c3d34001ba038d46a8c318a674d972c0e08c6 100644 (file)
--- a/libs/backends/alsa/alsa_audiobackend.h
+++ b/libs/backends/alsa/alsa_audiobackend.h
@@ -141,10 +141,13 @@ class AlsaMidiPort : public AlsaPort {
                DataType type () const { return DataType::MIDI; };
 
                void* get_buffer (pframes_t nframes);
-               const AlsaMidiBuffer const_buffer () const { return _buffer; }
+               const AlsaMidiBuffer const_buffer () const { return _buffer[_bufperiod]; }
+
+               void next_period() { get_buffer(0); _bufperiod = (_bufperiod + 1) % 2; }
 
        private:
-               AlsaMidiBuffer _buffer;
+               AlsaMidiBuffer _buffer[2];
+               int _bufperiod;
 }; // class AlsaMidiPort
 
 class AlsaAudioBackend : public AudioBackend {