alsa-backend: drop midi during freewheel processing.

diff --git a/libs/backends/alsa/alsa_audiobackend.cc b/libs/backends/alsa/alsa_audiobackend.cc
index 524036c07b86471a7b6a0aab1e6973a8b3ceda60..3ccc97ec946e427b82586011ce15b1172b274a4e 100644 (file)
--- a/libs/backends/alsa/alsa_audiobackend.cc
+++ b/libs/backends/alsa/alsa_audiobackend.cc
@@ -1432,7 +1432,7 @@ AlsaAudioBackend::main_process_thread ()
                                }
                                _pcmi->capt_done (_samples_per_period);
 
-                               /* de-queue midi*/
+                               /* de-queue incoming midi*/
                                i = 0;
                                for (std::vector<AlsaPort*>::const_iterator it = _system_midi_in.begin (); it != _system_midi_in.end (); ++it, ++i) {
                                        assert (_rmidi_in.size() > i);
@@ -1459,12 +1459,11 @@ 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) {
+                               for (std::vector<AlsaPort*>::iterator it = _system_midi_out.begin (); it != _system_midi_out.end (); ++it) {
                                        static_cast<AlsaMidiPort*>(*it)->next_period();
                                }
 
-                               /* queue midi */
+                               /* queue outgoing 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);
@@ -1504,17 +1503,42 @@ AlsaAudioBackend::main_process_thread ()
                        }
                } else {
                        // Freewheelin'
+
+                       // zero audio input buffers
                        for (std::vector<AlsaPort*>::const_iterator it = _system_inputs.begin (); it != _system_inputs.end (); ++it) {
                                memset ((*it)->get_buffer (_samples_per_period), 0, _samples_per_period * sizeof (Sample));
                        }
-                       for (std::vector<AlsaPort*>::const_iterator it = _system_midi_in.begin (); it != _system_midi_in.end (); ++it) {
+
+                       clock1 = g_get_monotonic_time();
+                       uint32_t i = 0;
+                       for (std::vector<AlsaPort*>::const_iterator it = _system_midi_in.begin (); it != _system_midi_in.end (); ++it, ++i) {
                                static_cast<AlsaMidiBuffer*>((*it)->get_buffer(0))->clear ();
+                               AlsaMidiIn *rm = _rmidi_in.at(i);
+                               void *bptr = (*it)->get_buffer(0);
+                               midi_clear(bptr); // zero midi buffer
+
+                               // TODO add an API call for this.
+                               pframes_t time;
+                               uint8_t data[64]; // match MaxAlsaEventSize in alsa_rawmidi.cc
+                               size_t size = sizeof(data);
+                               while (rm->recv_event (time, data, size)) {
+                                       ; // discard midi-data from HW.
+                               }
+                               rm->sync_time (clock1);
                        }
 
                        if (engine.process_callback (_samples_per_period)) {
                                _pcmi->pcm_stop ();
+                               _active = false;
                                return 0;
                        }
+
+                       // drop all outgoing MIDI messages
+                       for (std::vector<AlsaPort*>::const_iterator it = _system_midi_out.begin (); it != _system_midi_out.end (); ++it) {
+                                       void *bptr = (*it)->get_buffer(0);
+                                       midi_clear(bptr);
+                       }
+
                        _dsp_load = 1.0;
                        Glib::usleep (100); // don't hog cpu
                }