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Commit 5d285ff9 authored by Sam Lantinga's avatar Sam Lantinga
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Fixed bug #79 

Implemented snd_pcm_sw_params_set_start_threshold() and snd_pcm_sw_params_set_avail_min() in the ALSA 0.9 driver.
This doesn't actually change any latency for me, but it's the right thing to do...

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%401556
parent 9b2bff03
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Showing with 68 additions and 12 deletions
src/audio/alsa/SDL_alsa_audio.c
View file @ 5d285ff9
...@@ -69,6 +69,7 @@ static int (*SDL_NAME(snd_pcm_prepare))(snd_pcm_t *pcm); ...@@ -69,6 +69,7 @@ static int (*SDL_NAME(snd_pcm_prepare))(snd_pcm_t *pcm);
static int (*SDL_NAME(snd_pcm_drain))(snd_pcm_t *pcm); static int (*SDL_NAME(snd_pcm_drain))(snd_pcm_t *pcm);
static const char *(*SDL_NAME(snd_strerror))(int errnum); static const char *(*SDL_NAME(snd_strerror))(int errnum);
static size_t (*SDL_NAME(snd_pcm_hw_params_sizeof))(void); static size_t (*SDL_NAME(snd_pcm_hw_params_sizeof))(void);
static size_t (*SDL_NAME(snd_pcm_sw_params_sizeof))(void);
static int (*SDL_NAME(snd_pcm_hw_params_any))(snd_pcm_t *pcm, snd_pcm_hw_params_t *params); static int (*SDL_NAME(snd_pcm_hw_params_any))(snd_pcm_t *pcm, snd_pcm_hw_params_t *params);
static int (*SDL_NAME(snd_pcm_hw_params_set_access))(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_t access); static int (*SDL_NAME(snd_pcm_hw_params_set_access))(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_t access);
static int (*SDL_NAME(snd_pcm_hw_params_set_format))(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_t val); static int (*SDL_NAME(snd_pcm_hw_params_set_format))(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_t val);
...@@ -79,7 +80,16 @@ static snd_pcm_uframes_t (*SDL_NAME(snd_pcm_hw_params_set_period_size_near))(snd ...@@ -79,7 +80,16 @@ static snd_pcm_uframes_t (*SDL_NAME(snd_pcm_hw_params_set_period_size_near))(snd
static unsigned int (*SDL_NAME(snd_pcm_hw_params_set_periods_near))(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int *dir); static unsigned int (*SDL_NAME(snd_pcm_hw_params_set_periods_near))(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int *dir);
static int (*SDL_NAME(snd_pcm_hw_params))(snd_pcm_t *pcm, snd_pcm_hw_params_t *params); static int (*SDL_NAME(snd_pcm_hw_params))(snd_pcm_t *pcm, snd_pcm_hw_params_t *params);
static int (*SDL_NAME(snd_pcm_nonblock))(snd_pcm_t *pcm, int nonblock); static int (*SDL_NAME(snd_pcm_nonblock))(snd_pcm_t *pcm, int nonblock);
/*
static unsigned int (*SDL_NAME(snd_pcm_hw_params_get_period_size))(const snd_pcm_hw_params_t *params);
static int (*SDL_NAME(snd_pcm_hw_params_get_periods))(snd_pcm_hw_params_t *params);
*/
static int (*SDL_NAME(snd_pcm_sw_params_current))(snd_pcm_t *pcm, snd_pcm_sw_params_t *swparams);
static int (*SDL_NAME(snd_pcm_sw_params_set_start_threshold))(snd_pcm_t *pcm, snd_pcm_sw_params_t *params, snd_pcm_uframes_t val);
static int (*SDL_NAME(snd_pcm_sw_params_set_avail_min))(snd_pcm_t *pcm, snd_pcm_sw_params_t *params, snd_pcm_uframes_t val);
static int (*SDL_NAME(snd_pcm_sw_params))(snd_pcm_t *pcm, snd_pcm_sw_params_t *params);
#define snd_pcm_hw_params_sizeof SDL_NAME(snd_pcm_hw_params_sizeof) #define snd_pcm_hw_params_sizeof SDL_NAME(snd_pcm_hw_params_sizeof)
#define snd_pcm_sw_params_sizeof SDL_NAME(snd_pcm_sw_params_sizeof)
/* cast funcs to char* first, to please GCC's strict aliasing rules. */ /* cast funcs to char* first, to please GCC's strict aliasing rules. */
static struct { static struct {
...@@ -94,6 +104,7 @@ static struct { ...@@ -94,6 +104,7 @@ static struct {
{ "snd_pcm_drain", (void**)(char*)&SDL_NAME(snd_pcm_drain) }, { "snd_pcm_drain", (void**)(char*)&SDL_NAME(snd_pcm_drain) },
{ "snd_strerror", (void**)(char*)&SDL_NAME(snd_strerror) }, { "snd_strerror", (void**)(char*)&SDL_NAME(snd_strerror) },
{ "snd_pcm_hw_params_sizeof", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_sizeof) }, { "snd_pcm_hw_params_sizeof", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_sizeof) },
{ "snd_pcm_sw_params_sizeof", (void**)(char*)&SDL_NAME(snd_pcm_sw_params_sizeof) },
{ "snd_pcm_hw_params_any", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_any) }, { "snd_pcm_hw_params_any", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_any) },
{ "snd_pcm_hw_params_set_access", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_set_access) }, { "snd_pcm_hw_params_set_access", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_set_access) },
{ "snd_pcm_hw_params_set_format", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_set_format) }, { "snd_pcm_hw_params_set_format", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_set_format) },
...@@ -104,6 +115,14 @@ static struct { ...@@ -104,6 +115,14 @@ static struct {
{ "snd_pcm_hw_params_set_periods_near", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_set_periods_near) }, { "snd_pcm_hw_params_set_periods_near", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_set_periods_near) },
{ "snd_pcm_hw_params", (void**)(char*)&SDL_NAME(snd_pcm_hw_params) }, { "snd_pcm_hw_params", (void**)(char*)&SDL_NAME(snd_pcm_hw_params) },
{ "snd_pcm_nonblock", (void**)(char*)&SDL_NAME(snd_pcm_nonblock) }, { "snd_pcm_nonblock", (void**)(char*)&SDL_NAME(snd_pcm_nonblock) },
/*
{ "snd_pcm_hw_params_get_period_size", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_get_period_size) },
{ "snd_pcm_hw_params_get_periods", (void**)(char*)&SDL_NAME(snd_pcm_hw_params_get_periods) },
*/
{ "snd_pcm_sw_params_current", (void**)(char*)&SDL_NAME(snd_pcm_sw_params_current) },
{ "snd_pcm_sw_params_set_start_threshold", (void**)(char*)&SDL_NAME(snd_pcm_sw_params_set_start_threshold) },
{ "snd_pcm_sw_params_set_avail_min", (void**)(char*)&SDL_NAME(snd_pcm_sw_params_set_avail_min) },
{ "snd_pcm_sw_params", (void**)(char*)&SDL_NAME(snd_pcm_sw_params) },
}; };
static void UnloadALSALibrary(void) { static void UnloadALSALibrary(void) {
...@@ -304,7 +323,8 @@ static void ALSA_CloseAudio(_THIS) ...@@ -304,7 +323,8 @@ static void ALSA_CloseAudio(_THIS)
static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec) static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec)
{ {
int status; int status;
snd_pcm_hw_params_t *params; snd_pcm_hw_params_t *hwparams;
snd_pcm_sw_params_t *swparams;
snd_pcm_format_t format; snd_pcm_format_t format;
snd_pcm_uframes_t frames; snd_pcm_uframes_t frames;
Uint16 test_format; Uint16 test_format;
...@@ -319,8 +339,8 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec) ...@@ -319,8 +339,8 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec)
} }
/* Figure out what the hardware is capable of */ /* Figure out what the hardware is capable of */
snd_pcm_hw_params_alloca(&params); snd_pcm_hw_params_alloca(&hwparams);
status = SDL_NAME(snd_pcm_hw_params_any)(pcm_handle, params); status = SDL_NAME(snd_pcm_hw_params_any)(pcm_handle, hwparams);
if ( status < 0 ) { if ( status < 0 ) {
SDL_SetError("Couldn't get hardware config: %s", SDL_NAME(snd_strerror)(status)); SDL_SetError("Couldn't get hardware config: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this); ALSA_CloseAudio(this);
...@@ -328,7 +348,7 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec) ...@@ -328,7 +348,7 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec)
} }
/* SDL only uses interleaved sample output */ /* SDL only uses interleaved sample output */
status = SDL_NAME(snd_pcm_hw_params_set_access)(pcm_handle, params, SND_PCM_ACCESS_RW_INTERLEAVED); status = SDL_NAME(snd_pcm_hw_params_set_access)(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED);
if ( status < 0 ) { if ( status < 0 ) {
SDL_SetError("Couldn't set interleaved access: %s", SDL_NAME(snd_strerror)(status)); SDL_SetError("Couldn't set interleaved access: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this); ALSA_CloseAudio(this);
...@@ -363,7 +383,7 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec) ...@@ -363,7 +383,7 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec)
break; break;
} }
if ( format != 0 ) { if ( format != 0 ) {
status = SDL_NAME(snd_pcm_hw_params_set_format)(pcm_handle, params, format); status = SDL_NAME(snd_pcm_hw_params_set_format)(pcm_handle, hwparams, format);
} }
if ( status < 0 ) { if ( status < 0 ) {
test_format = SDL_NextAudioFormat(); test_format = SDL_NextAudioFormat();
...@@ -377,9 +397,9 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec) ...@@ -377,9 +397,9 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec)
spec->format = test_format; spec->format = test_format;
/* Set the number of channels */ /* Set the number of channels */
status = SDL_NAME(snd_pcm_hw_params_set_channels)(pcm_handle, params, spec->channels); status = SDL_NAME(snd_pcm_hw_params_set_channels)(pcm_handle, hwparams, spec->channels);
if ( status < 0 ) { if ( status < 0 ) {
status = SDL_NAME(snd_pcm_hw_params_get_channels)(params); status = SDL_NAME(snd_pcm_hw_params_get_channels)(hwparams);
if ( (status <= 0) || (status > 2) ) { if ( (status <= 0) || (status > 2) ) {
SDL_SetError("Couldn't set audio channels"); SDL_SetError("Couldn't set audio channels");
ALSA_CloseAudio(this); ALSA_CloseAudio(this);
...@@ -389,7 +409,7 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec) ...@@ -389,7 +409,7 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec)
} }
/* Set the audio rate */ /* Set the audio rate */
status = SDL_NAME(snd_pcm_hw_params_set_rate_near)(pcm_handle, params, spec->freq, NULL); status = SDL_NAME(snd_pcm_hw_params_set_rate_near)(pcm_handle, hwparams, spec->freq, NULL);
if ( status < 0 ) { if ( status < 0 ) {
SDL_SetError("Couldn't set audio frequency: %s", SDL_NAME(snd_strerror)(status)); SDL_SetError("Couldn't set audio frequency: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this); ALSA_CloseAudio(this);
...@@ -399,14 +419,50 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec) ...@@ -399,14 +419,50 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec)
/* Set the buffer size, in samples */ /* Set the buffer size, in samples */
frames = spec->samples; frames = spec->samples;
frames = SDL_NAME(snd_pcm_hw_params_set_period_size_near)(pcm_handle, params, frames, NULL); frames = SDL_NAME(snd_pcm_hw_params_set_period_size_near)(pcm_handle, hwparams, frames, NULL);
spec->samples = frames; spec->samples = frames;
SDL_NAME(snd_pcm_hw_params_set_periods_near)(pcm_handle, params, 2, NULL); SDL_NAME(snd_pcm_hw_params_set_periods_near)(pcm_handle, hwparams, 2, NULL);
/* "set" the hardware with the desired parameters */ /* "set" the hardware with the desired parameters */
status = SDL_NAME(snd_pcm_hw_params)(pcm_handle, params); status = SDL_NAME(snd_pcm_hw_params)(pcm_handle, hwparams);
if ( status < 0 ) {
SDL_SetError("Couldn't set hardware audio parameters: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
/*
{ unsigned int bufsize; int fragments;
bufsize = SDL_NAME(snd_pcm_hw_params_get_period_size)(hwparams);
fragments = SDL_NAME(snd_pcm_hw_params_get_periods)(hwparams);
fprintf(stderr, "ALSA: bufsize = %ld, fragments = %d\n", bufsize, fragments);
}
*/
/* Set the software parameters */
snd_pcm_sw_params_alloca(&swparams);
status = SDL_NAME(snd_pcm_sw_params_current)(pcm_handle, swparams);
if ( status < 0 ) {
SDL_SetError("Couldn't get software config: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
status = SDL_NAME(snd_pcm_sw_params_set_start_threshold)(pcm_handle, swparams, 0);
if ( status < 0 ) {
SDL_SetError("Couldn't set start threshold: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
status = SDL_NAME(snd_pcm_sw_params_set_avail_min)(pcm_handle, swparams, frames);
if ( status < 0 ) {
SDL_SetError("Couldn't set avail min: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
status = SDL_NAME(snd_pcm_sw_params)(pcm_handle, swparams);
if ( status < 0 ) { if ( status < 0 ) {
SDL_SetError("Couldn't set audio parameters: %s", SDL_NAME(snd_strerror)(status)); SDL_SetError("Couldn't set software audio parameters: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this); ALSA_CloseAudio(this);
return(-1); return(-1);
} }
......
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