]> de.git.xonotic.org Git - xonotic/darkplaces.git/blobdiff - snd_alsa.c
snd_alsa: MIDI input support! MIDI events get mapped to MIDINOTE<n> events (n = 0...
[xonotic/darkplaces.git] / snd_alsa.c
index 30237fc34d37ff370d0bb0d072fa4272737f3253..59c85edfcacb9ac79ae3b6aa21e81c4d99b575fb 100644 (file)
@@ -1,10 +1,5 @@
 /*
-       snd_alsa.c
-
-       Support for the ALSA 1.0.1 sound driver
-
-       Copyright (C) 1999,2000  contributors of the QuakeForge project
-       Please see the file "AUTHORS" for a list of contributors
+       Copyright (C) 2006  Mathieu Olivier
 
        This program is free software; you can redistribute it and/or
        modify it under the terms of the GNU General Public License
 
 */
 
-#include <alsa/asoundlib.h>
+// ALSA module, used by Linux
 
 #include "quakedef.h"
+
+#include <alsa/asoundlib.h>
+
 #include "snd_main.h"
 
-static int                     snd_inited;
-static snd_pcm_uframes_t buffer_size;
 
-static const char  *pcmname = NULL;
-static snd_pcm_t   *pcm;
+#define NB_PERIODS 2
 
-qboolean SNDDMA_Init (void)
-{
-       int                                      err, i;
-       int                                      bps = -1, stereo = -1;
-       unsigned int             rate = 0;
-       snd_pcm_hw_params_t     *hw;
-       snd_pcm_sw_params_t     *sw;
-       snd_pcm_uframes_t        frag_size;
+static snd_pcm_t* pcm_handle = NULL;
+static snd_pcm_sframes_t expected_delay = 0;
+static unsigned int alsasoundtime;
 
-       snd_pcm_hw_params_alloca (&hw);
-       snd_pcm_sw_params_alloca (&sw);
+static snd_seq_t* seq_handle = NULL;
 
-// COMMANDLINEOPTION: Linux ALSA Sound: -sndpcm <devicename> selects which pcm device to us, default is "default"
-       if ((i=COM_CheckParm("-sndpcm"))!=0)
-               pcmname=com_argv[i+1];
-       if (!pcmname)
-               pcmname = "default";
+/*
+====================
+SndSys_Init
 
-// COMMANDLINEOPTION: Linux ALSA Sound: -sndbits <number> sets sound precision to 8 or 16 bit (email me if you want others added)
-       if ((i=COM_CheckParm("-sndbits")) != 0)
+Create "snd_renderbuffer" with the proper sound format if the call is successful
+May return a suggested format if the requested format isn't available
+====================
+*/
+qboolean SndSys_Init (const snd_format_t* requested, snd_format_t* suggested)
+{
+       const char* pcm_name, *seq_name;
+       int i, err, seq_client, seq_port;
+       snd_pcm_hw_params_t* hw_params = NULL;
+       snd_pcm_format_t snd_pcm_format;
+       snd_pcm_uframes_t buffer_size;
+
+       Con_Print ("SndSys_Init: using the ALSA module\n");
+
+       seq_name = NULL;
+       i = COM_CheckParm ("-sndseqin"); // TODO turn this into a cvar, maybe
+       if (i != 0 && i < com_argc - 1)
+               seq_name = com_argv[i + 1];
+       if(seq_name)
        {
-               bps = atoi(com_argv[i+1]);
-               if (bps != 16 && bps != 8)
+               seq_client = atoi(seq_name);
+               seq_port = 0;
+               if(strchr(seq_name, ':'))
+                       seq_port = atoi(strchr(seq_name, ':') + 1);
+               Con_Printf ("SndSys_Init: seq input port has been set to \"%d:%d\". Enabling sequencer input...\n", seq_client, seq_port);
+               err = snd_seq_open (&seq_handle, "default", SND_SEQ_OPEN_INPUT, 0);
+               if (err < 0)
                {
-                       Con_Printf("Error: invalid sample bits: %d\n", bps);
-                       return false;
+                       Con_Print ("SndSys_Init: can't open seq device\n");
+                       goto seqdone;
                }
+               err = snd_seq_set_client_name(seq_handle, gamename);
+               if (err < 0)
+               {
+                       Con_Print ("SndSys_Init: can't set name of seq device\n");
+                       goto seqerror;
+               }
+               err = snd_seq_create_simple_port(seq_handle, gamename, SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE, SND_SEQ_PORT_TYPE_MIDI_GENERIC | SND_SEQ_PORT_TYPE_APPLICATION);
+               if(err < 0)
+               {
+                       Con_Print ("SndSys_Init: can't create seq port\n");
+                       goto seqerror;
+               }
+               err = snd_seq_connect_from(seq_handle, 0, seq_client, seq_port);
+               if(err < 0)
+               {
+                       Con_Printf ("SndSys_Init: can't connect to seq port \"%d:%d\"\n", seq_client, seq_port);
+                       goto seqerror;
+               }
+               err = snd_seq_nonblock(seq_handle, 1);
+               if(err < 0)
+               {
+                       Con_Print ("SndSys_Init: can't make seq nonblocking\n");
+                       goto seqerror;
+               }
+
+               goto seqdone;
+
+seqerror:
+               snd_seq_close(seq_handle);
+               seq_handle = NULL;
        }
 
-// COMMANDLINEOPTION: Linux ALSA Sound: -sndspeed <hz> chooses 44100 hz, 22100 hz, or 11025 hz sound output rate
-       if ((i=COM_CheckParm("-sndspeed")) != 0)
+seqdone:
+       // Check the requested sound format
+       if (requested->width < 1 || requested->width > 2)
        {
-               rate = atoi(com_argv[i+1]);
-               if (rate!=44100 && rate!=22050 && rate!=11025)
+               Con_Printf ("SndSys_Init: invalid sound width (%hu)\n",
+                                       requested->width);
+
+               if (suggested != NULL)
                {
-                       Con_Printf("Error: invalid sample rate: %d\n", rate);
-                       return false;
-               }
-       }
+                       memcpy (suggested, requested, sizeof (*suggested));
 
-// COMMANDLINEOPTION: Linux ALSA Sound: -sndmono sets sound output to mono
-       if ((i=COM_CheckParm("-sndmono")) != 0)
-               stereo=0;
-// COMMANDLINEOPTION: Linux ALSA Sound: -sndstereo sets sound output to stereo
-       if ((i=COM_CheckParm("-sndstereo")) != 0)
-               stereo=1;
-
-       err = snd_pcm_open (&pcm, pcmname, SND_PCM_STREAM_PLAYBACK,
-                                                 SND_PCM_NONBLOCK);
-       if (0 > err) {
-               Con_Printf ("Error: audio open error: %s\n", snd_strerror (err));
-               return 0;
-       }
-       Con_Printf ("ALSA: Using PCM %s.\n", pcmname);
+                       if (requested->width < 1)
+                               suggested->width = 1;
+                       else
+                               suggested->width = 2;
 
-       err = snd_pcm_hw_params_any (pcm, hw);
-       if (0 > err) {
-               Con_Printf ("ALSA: error setting hw_params_any. %s\n",
-                                       snd_strerror (err));
-               goto error;
-       }
+                       Con_Printf ("SndSys_Init: suggesting sound width = %hu\n",
+                                               suggested->width);
+               }
 
-       err = snd_pcm_hw_params_set_access (pcm, hw,
-                                                                                 SND_PCM_ACCESS_MMAP_INTERLEAVED);
-       if (0 > err) {
-               Con_Printf ("ALSA: Failure to set noninterleaved PCM access. %s\n"
-                                       "Note: Interleaved is not supported\n",
-                                       snd_strerror (err));
-               goto error;
+               return false;
+    }
+
+       if (pcm_handle != NULL)
+       {
+               Con_Print ("SndSys_Init: WARNING: Init called before Shutdown!\n");
+               SndSys_Shutdown ();
        }
 
-       switch (bps) {
-               case -1:
-                       err = snd_pcm_hw_params_set_format (pcm, hw,
-                                                                                                 SND_PCM_FORMAT_S16);
-                       if (0 <= err) {
-                               bps = 16;
-                       } else if (0 <= (err = snd_pcm_hw_params_set_format (pcm, hw,
-                                                                                                                SND_PCM_FORMAT_U8))) {
-                               bps = 8;
-                       } else {
-                               Con_Printf ("ALSA: no useable formats. %s\n",
-                                                       snd_strerror (err));
-                               goto error;
-                       }
+       // Determine the name of the PCM handle we'll use
+       switch (requested->channels)
+       {
+               case 4:
+                       pcm_name = "surround40";
+                       break;
+               case 6:
+                       pcm_name = "surround51";
                        break;
                case 8:
-               case 16:
-                       err = snd_pcm_hw_params_set_format (pcm, hw, bps == 8 ?
-                                                                                                 SND_PCM_FORMAT_U8 :
-                                                                                                 SND_PCM_FORMAT_S16);
-                       if (0 > err) {
-                               Con_Printf ("ALSA: no usable formats. %s\n",
-                                                       snd_strerror (err));
-                               goto error;
-                       }
+                       pcm_name = "surround71";
                        break;
                default:
-                       Con_Printf ("ALSA: desired format not supported\n");
-                       goto error;
-       }
-
-       switch (stereo) {
-               case -1:
-                       err = snd_pcm_hw_params_set_channels (pcm, hw, 2);
-                       if (0 <= err) {
-                               stereo = 1;
-                       } else if (0 <= (err = snd_pcm_hw_params_set_channels (pcm, hw,
-                                                                                                                                        1))) {
-                               stereo = 0;
-                       } else {
-                               Con_Printf ("ALSA: no usable channels. %s\n",
-                                                       snd_strerror (err));
-                               goto error;
-                       }
-                       break;
-               case 0:
-               case 1:
-                       err = snd_pcm_hw_params_set_channels (pcm, hw, stereo ? 2 : 1);
-                       if (0 > err) {
-                               Con_Printf ("ALSA: no usable channels. %s\n",
-                                                       snd_strerror (err));
-                               goto error;
-                       }
+                       pcm_name = "default";
                        break;
-               default:
-                       Con_Printf ("ALSA: desired channels not supported\n");
-                       goto error;
        }
-
-       switch (rate) {
-               case 0:
-                       rate = 44100;
-                       err = snd_pcm_hw_params_set_rate_near (pcm, hw, &rate, 0);
-                       if (0 <= err) {
-                               frag_size = 32 * bps;
-                       } else {
-                               rate = 22050;
-                               err = snd_pcm_hw_params_set_rate_near (pcm, hw, &rate, 0);
-                               if (0 <= err) {
-                                       frag_size = 16 * bps;
-                               } else {
-                                       rate = 11025;
-                                       err = snd_pcm_hw_params_set_rate_near (pcm, hw, &rate,
-                                                                                                                        0);
-                                       if (0 <= err) {
-                                               frag_size = 8 * bps;
-                                       } else {
-                                               Con_Printf ("ALSA: no usable rates. %s\n",
-                                                                       snd_strerror (err));
-                                               goto error;
-                                       }
-                               }
-                       }
-                       break;
-               case 11025:
-               case 22050:
-               case 44100:
-                       err = snd_pcm_hw_params_set_rate_near (pcm, hw, &rate, 0);
-                       if (0 > err) {
-                               Con_Printf ("ALSA: desired rate %i not supported. %s\n", rate,
-                                                       snd_strerror (err));
-                               goto error;
-                       }
-                       frag_size = 8 * bps * rate / 11025;
-                       break;
-               default:
-                       Con_Printf ("ALSA: desired rate %i not supported.\n", rate);
-                       goto error;
+// COMMANDLINEOPTION: Linux ALSA Sound: -sndpcm <devicename> selects which pcm device to us, default is "default"
+       i = COM_CheckParm ("-sndpcm");
+       if (i != 0 && i < com_argc - 1)
+               pcm_name = com_argv[i + 1];
+
+       // Open the audio device
+       Con_Printf ("SndSys_Init: PCM device is \"%s\"\n", pcm_name);
+       err = snd_pcm_open (&pcm_handle, pcm_name, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Init: can't open audio device \"%s\" (%s)\n",
+                                       pcm_name, snd_strerror (err));
+               return false;
        }
 
-       err = snd_pcm_hw_params_set_period_size_near (pcm, hw, &frag_size, 0);
-       if (0 > err) {
-               Con_Printf ("ALSA: unable to set period size near %i. %s\n",
-                                       (int) frag_size, snd_strerror (err));
-               goto error;
-       }
-       err = snd_pcm_hw_params (pcm, hw);
-       if (0 > err) {
-               Con_Printf ("ALSA: unable to install hw params: %s\n",
+       // Allocate the hardware parameters
+       err = snd_pcm_hw_params_malloc (&hw_params);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Init: can't allocate hardware parameters (%s)\n",
                                        snd_strerror (err));
-               goto error;
+               goto init_error;
        }
-       err = snd_pcm_sw_params_current (pcm, sw);
-       if (0 > err) {
-               Con_Printf ("ALSA: unable to determine current sw params. %s\n",
+       err = snd_pcm_hw_params_any (pcm_handle, hw_params);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Init: can't initialize hardware parameters (%s)\n",
                                        snd_strerror (err));
-               goto error;
+               goto init_error;
        }
-       err = snd_pcm_sw_params_set_start_threshold (pcm, sw, ~0U);
-       if (0 > err) {
-               Con_Printf ("ALSA: unable to set playback threshold. %s\n",
+
+       // Set the access type
+       err = snd_pcm_hw_params_set_access (pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Init: can't set access type (%s)\n",
                                        snd_strerror (err));
-               goto error;
+               goto init_error;
        }
-       err = snd_pcm_sw_params_set_stop_threshold (pcm, sw, ~0U);
-       if (0 > err) {
-               Con_Printf ("ALSA: unable to set playback stop threshold. %s\n",
-                                       snd_strerror (err));
-               goto error;
+
+       // Set the sound width
+       if (requested->width == 1)
+               snd_pcm_format = SND_PCM_FORMAT_U8;
+       else
+               snd_pcm_format = SND_PCM_FORMAT_S16;
+       err = snd_pcm_hw_params_set_format (pcm_handle, hw_params, snd_pcm_format);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Init: can't set sound width to %hu (%s)\n",
+                                       requested->width, snd_strerror (err));
+               goto init_error;
        }
-       err = snd_pcm_sw_params (pcm, sw);
-       if (0 > err) {
-               Con_Printf ("ALSA: unable to install sw params. %s\n",
-                                       snd_strerror (err));
-               goto error;
+
+       // Set the sound channels
+       err = snd_pcm_hw_params_set_channels (pcm_handle, hw_params, requested->channels);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Init: can't set sound channels to %hu (%s)\n",
+                                       requested->channels, snd_strerror (err));
+               goto init_error;
        }
 
-       shm->format.channels = stereo + 1;
-       shm->samplepos = 0;
-       shm->format.width = bps / 8;
+       // Set the sound speed
+       err = snd_pcm_hw_params_set_rate (pcm_handle, hw_params, requested->speed, 0);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Init: can't set sound speed to %u (%s)\n",
+                                       requested->speed, snd_strerror (err));
+               goto init_error;
+       }
+
+       buffer_size = requested->speed / 5;
+       err = snd_pcm_hw_params_set_buffer_size_near (pcm_handle, hw_params, &buffer_size);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Init: can't set sound buffer size to %lu (%s)\n",
+                                       buffer_size, snd_strerror (err));
+               goto init_error;
+       }
 
-       err = snd_pcm_hw_params_get_buffer_size (hw, &buffer_size);
-       if (0 > err) {
-               Con_Printf ("ALSA: unable to get buffer size. %s\n",
+       buffer_size /= NB_PERIODS;
+       err = snd_pcm_hw_params_set_period_size_near(pcm_handle, hw_params, &buffer_size, 0);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Init: can't set sound period size to %lu (%s)\n",
+                                       buffer_size, snd_strerror (err));
+               goto init_error;
+       }
+
+       err = snd_pcm_hw_params (pcm_handle, hw_params);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Init: can't set hardware parameters (%s)\n",
                                        snd_strerror (err));
-               goto error;
+               goto init_error;
        }
 
-       shm->samples = buffer_size * shm->format.channels;              // mono samples in buffer
-       shm->format.speed = rate;
-       SNDDMA_GetDMAPos ();            // sets shm->buffer
+       snd_pcm_hw_params_free (hw_params);
+
+       snd_renderbuffer = Snd_CreateRingBuffer(requested, 0, NULL);
+       expected_delay = 0;
+       alsasoundtime = 0;
+       if (snd_channellayout.integer == SND_CHANNELLAYOUT_AUTO)
+               Cvar_SetValueQuick (&snd_channellayout, SND_CHANNELLAYOUT_ALSA);
 
-       snd_inited = 1;
        return true;
 
-error:
-       snd_pcm_close (pcm);
+
+// It's not very clean, but it avoids a lot of duplicated code.
+init_error:
+
+       if (hw_params != NULL)
+               snd_pcm_hw_params_free (hw_params);
+
+       snd_pcm_close(pcm_handle);
+       pcm_handle = NULL;
+
        return false;
 }
 
-int SNDDMA_GetDMAPos (void)
+
+/*
+====================
+SndSys_Shutdown
+
+Stop the sound card, delete "snd_renderbuffer" and free its other resources
+====================
+*/
+void SndSys_Shutdown (void)
 {
-       const snd_pcm_channel_area_t *areas;
-       snd_pcm_uframes_t offset;
-       snd_pcm_uframes_t nframes = shm->samples/shm->format.channels;
+       if (seq_handle != NULL)
+       {
+               snd_seq_close(seq_handle);
+               seq_handle = NULL;
+       }
 
-       if (!snd_inited)
-               return 0;
+       if (pcm_handle != NULL)
+       {
+               snd_pcm_close(pcm_handle);
+               pcm_handle = NULL;
+       }
 
-       snd_pcm_avail_update (pcm);
-       snd_pcm_mmap_begin (pcm, &areas, &offset, &nframes);
-       offset *= shm->format.channels;
-       nframes *= shm->format.channels;
-       shm->samplepos = offset;
-       shm->buffer = (qbyte *)areas->addr;
-       return shm->samplepos;
+       if (snd_renderbuffer != NULL)
+       {
+               Mem_Free(snd_renderbuffer->ring);
+               Mem_Free(snd_renderbuffer);
+               snd_renderbuffer = NULL;
+       }
 }
 
-void SNDDMA_Shutdown (void)
+
+/*
+====================
+SndSys_Recover
+
+Try to recover from errors
+====================
+*/
+static qboolean SndSys_Recover (int err_num)
 {
-       if (snd_inited) {
-               snd_pcm_close (pcm);
-               snd_inited = 0;
+       int err;
+
+       // We can only do something on underrun ("broken pipe") errors
+       if (err_num != -EPIPE)
+               return false;
+
+       err = snd_pcm_prepare (pcm_handle);
+       if (err < 0)
+       {
+               Con_Printf ("SndSys_Recover: unable to recover (%s)\n",
+                                        snd_strerror (err));
+
+               // TOCHECK: should we stop the playback ?
+
+               return false;
        }
+
+       return true;
 }
 
+
 /*
-       SNDDMA_Submit
+====================
+SndSys_Write
+====================
+*/
+static snd_pcm_sframes_t SndSys_Write (const unsigned char* buffer, unsigned int nbframes)
+{
+       snd_pcm_sframes_t written;
+
+       written = snd_pcm_writei (pcm_handle, buffer, nbframes);
+       if (written < 0)
+       {
+               if (developer.integer >= 1000 && vid_activewindow)
+                       Con_Printf ("SndSys_Write: audio write returned %ld (%s)!\n",
+                                                written, snd_strerror (written));
 
-       Send sound to device if buffer isn't really the dma buffer
+               if (SndSys_Recover (written))
+               {
+                       written = snd_pcm_writei (pcm_handle, buffer, nbframes);
+                       if (written < 0)
+                               Con_DPrintf ("SndSys_Write: audio write failed again (error %ld: %s)!\n",
+                                                        written, snd_strerror (written));
+               }
+       }
+       if (written > 0)
+       {
+               snd_renderbuffer->startframe += written;
+               expected_delay += written;
+       }
+
+       return written;
+}
+
+
+/*
+====================
+SndSys_Submit
+
+Submit the contents of "snd_renderbuffer" to the sound card
+====================
 */
-void SNDDMA_Submit (void)
+void SndSys_Submit (void)
 {
-       int                     state;
-       int                     count = paintedtime - soundtime;
-       const snd_pcm_channel_area_t *areas;
-       snd_pcm_uframes_t nframes;
-       snd_pcm_uframes_t offset;
+       unsigned int startoffset, factor;
+       snd_pcm_uframes_t limit, nbframes;
+       snd_pcm_sframes_t written;
 
-       nframes = count / shm->format.channels;
+       if (pcm_handle == NULL ||
+               snd_renderbuffer->startframe == snd_renderbuffer->endframe)
+               return;
 
-       snd_pcm_avail_update (pcm);
-       snd_pcm_mmap_begin (pcm, &areas, &offset, &nframes);
+       startoffset = snd_renderbuffer->startframe % snd_renderbuffer->maxframes;
+       factor = snd_renderbuffer->format.width * snd_renderbuffer->format.channels;
+       limit = snd_renderbuffer->maxframes - startoffset;
+       nbframes = snd_renderbuffer->endframe - snd_renderbuffer->startframe;
 
-       state = snd_pcm_state (pcm);
+       if (nbframes > limit)
+       {
+               written = SndSys_Write (&snd_renderbuffer->ring[startoffset * factor], limit);
+               if (written < 0 || (snd_pcm_uframes_t)written != limit)
+                       return;
 
-       switch (state) {
-               case SND_PCM_STATE_PREPARED:
-                       snd_pcm_mmap_commit (pcm, offset, nframes);
-                       snd_pcm_start (pcm);
-                       break;
-               case SND_PCM_STATE_RUNNING:
-                       snd_pcm_mmap_commit (pcm, offset, nframes);
-                       break;
-               default:
-                       break;
+               nbframes -= limit;
+               startoffset = 0;
        }
+
+       written = SndSys_Write (&snd_renderbuffer->ring[startoffset * factor], nbframes);
+       if (written < 0)
+               return;
 }
 
-void *S_LockBuffer(void)
+
+/*
+====================
+SndSys_GetSoundTime
+
+Returns the number of sample frames consumed since the sound started
+====================
+*/
+unsigned int SndSys_GetSoundTime (void)
+{
+       snd_pcm_sframes_t delay, timediff;
+       int err;
+
+       if (pcm_handle == NULL)
+               return 0;
+
+       err = snd_pcm_delay (pcm_handle, &delay);
+       if (err < 0)
+       {
+               if (developer.integer >= 1000 && vid_activewindow)
+                       Con_DPrintf ("SndSys_GetSoundTime: can't get playback delay (%s)\n",
+                                                snd_strerror (err));
+
+               if (! SndSys_Recover (err))
+                       return 0;
+
+               err = snd_pcm_delay (pcm_handle, &delay);
+               if (err < 0)
+               {
+                       Con_DPrintf ("SndSys_GetSoundTime: can't get playback delay, again (%s)\n",
+                                                snd_strerror (err));
+                       return 0;
+               }
+       }
+
+       if (expected_delay < delay)
+       {
+               Con_DPrintf ("SndSys_GetSoundTime: expected_delay(%ld) < delay(%ld)\n",
+                                        expected_delay, delay);
+               timediff = 0;
+       }
+       else
+               timediff = expected_delay - delay;
+       expected_delay = delay;
+
+       alsasoundtime += (unsigned int)timediff;
+
+       return alsasoundtime;
+}
+
+
+/*
+====================
+SndSys_LockRenderBuffer
+
+Get the exclusive lock on "snd_renderbuffer"
+====================
+*/
+qboolean SndSys_LockRenderBuffer (void)
+{
+       // Nothing to do
+       return true;
+}
+
+
+/*
+====================
+SndSys_UnlockRenderBuffer
+
+Release the exclusive lock on "snd_renderbuffer"
+====================
+*/
+void SndSys_UnlockRenderBuffer (void)
 {
-       return shm->buffer;
+       // Nothing to do
 }
 
-void S_UnlockBuffer(void)
+/*
+====================
+SndSys_SendKeyEvents
+
+Send keyboard events originating from the sound system (e.g. MIDI)
+====================
+*/
+void SndSys_SendKeyEvents(void)
 {
+       snd_seq_event_t *event;
+       if(!seq_handle)
+               return;
+       for(;;)
+       {
+               if(snd_seq_event_input(seq_handle, &event) <= 0)
+                       break;
+               if(event)
+               {
+                       switch(event->type)
+                       {
+                               case SND_SEQ_EVENT_NOTEON:
+                                       if(event->data.note.velocity)
+                                       {
+                                               Key_Event(K_MIDINOTE0 + event->data.note.note, 0, true);
+                                               break;
+                                       }
+                               case SND_SEQ_EVENT_NOTEOFF:
+                                       Key_Event(K_MIDINOTE0 + event->data.note.note, 0, false);
+                                       break;
+                       }
+               }
+       }
 }