diff options
| -rw-r--r-- | backends/midi/alsa.cpp | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/backends/midi/alsa.cpp b/backends/midi/alsa.cpp index 1e8064efbd..06b55ceac5 100644 --- a/backends/midi/alsa.cpp +++ b/backends/midi/alsa.cpp @@ -83,10 +83,12 @@ private: snd_seq_t *seq_handle; int seq_client, seq_port; int my_client, my_port; + // The volume controller value of the first MIDI channel + int8 _channel0Volume; }; MidiDriver_ALSA::MidiDriver_ALSA(int client, int port) - : _isOpen(false), seq_handle(0), seq_client(client), seq_port(port), my_client(0), my_port(0) + : _isOpen(false), seq_handle(0), seq_client(client), seq_port(port), my_client(0), my_port(0), _channel0Volume(127) { memset(&ev, 0, sizeof(ev)); } @@ -208,15 +210,33 @@ void MidiDriver_ALSA::send(uint32 b) { case 0xB0: /* is it this simple ? Wow... */ snd_seq_ev_set_controller(&ev, chanID, midiCmd[1], midiCmd[2]); + + // We save the volume of the first MIDI channel here to utilize it in + // our workaround for broken USB-MIDI cables. + if (chanID == 0 && midiCmd[1] == 0x07) + _channel0Volume = midiCmd[2]; + send_event(1); break; case 0xC0: snd_seq_ev_set_pgmchange(&ev, chanID, midiCmd[1]); send_event(0); + + // Send a volume change command to work around a firmware bug in common + // USB-MIDI cables. If the first MIDI command in a USB packet is a + // Cx or Dx command, the second command in the packet is dropped + // somewhere. + send(0x07B0 | (_channel0Volume << 16)); break; case 0xD0: snd_seq_ev_set_chanpress(&ev, chanID, midiCmd[1]); send_event(1); + + // Send a volume change command to work around a firmware bug in common + // USB-MIDI cables. If the first MIDI command in a USB packet is a + // Cx or Dx command, the second command in the packet is dropped + // somewhere. + send(0x07B0 | (_channel0Volume << 16)); break; case 0xE0:{ // long theBend = ((((long)midiCmd[1] + (long)(midiCmd[2] << 7))) - 0x2000) / 4; |