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PCM - Change the hw_params determination order

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In snd_pcm_hw_params_choose(), set the buffer size before the period
size and time as default.  This will give more useful configuration for
most of apps, i.e. larger buffer size.

For apps that require the old behavior, now the function checks the
environment variable $LIBASOUND_COMPAT.  If this variable is set to
non-empty, the hw_params is determined in the old way, first period
then buffer sizes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2009-09-09 14:16:06 +02:00
parent 1f126fd7c6
commit cd7070bf4b
1 changed files with 24 additions and 9 deletions
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33
src/pcm/pcm_params.c
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@ -1081,6 +1081,7 @@ int snd_pcm_hw_param_never_eq(const snd_pcm_hw_params_t *params,
static int snd_pcm_hw_params_choose(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
{
int err;
const char *compat = getenv("LIBASOUND_COMPAT");
#ifdef CHOOSE_DEBUG
snd_output_t *log;
snd_output_stdio_attach(&log, stderr, 0);
@ -1103,15 +1104,29 @@ static int snd_pcm_hw_params_choose(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
err = snd_pcm_hw_param_set_first(pcm, params, SND_PCM_HW_PARAM_RATE, NULL, 0);
if (err < 0)
return err;
err = snd_pcm_hw_param_set_first(pcm, params, SND_PCM_HW_PARAM_PERIOD_TIME, NULL, 0);
if (err < 0)
return err;
err = snd_pcm_hw_param_set_first(pcm, params, SND_PCM_HW_PARAM_PERIOD_SIZE, NULL, 0);
if (err < 0)
return err;
err = snd_pcm_hw_param_set_last(pcm, params, SND_PCM_HW_PARAM_BUFFER_SIZE, NULL, 0);
if (err < 0)
return err;
if (compat && *compat) {
/* old mode */
err = snd_pcm_hw_param_set_first(pcm, params, SND_PCM_HW_PARAM_PERIOD_TIME, NULL, 0);
if (err < 0)
return err;
err = snd_pcm_hw_param_set_first(pcm, params, SND_PCM_HW_PARAM_PERIOD_SIZE, NULL, 0);
if (err < 0)
return err;
err = snd_pcm_hw_param_set_last(pcm, params, SND_PCM_HW_PARAM_BUFFER_SIZE, NULL, 0);
if (err < 0)
return err;
} else {
/* determine buffer size first */
err = snd_pcm_hw_param_set_last(pcm, params, SND_PCM_HW_PARAM_BUFFER_SIZE, NULL, 0);
if (err < 0)
return err;
err = snd_pcm_hw_param_set_first(pcm, params, SND_PCM_HW_PARAM_PERIOD_SIZE, NULL, 0);
if (err < 0)
return err;
err = snd_pcm_hw_param_set_first(pcm, params, SND_PCM_HW_PARAM_PERIOD_TIME, NULL, 0);
if (err < 0)
return err;
}
err = snd_pcm_hw_param_set_first(pcm, params, SND_PCM_HW_PARAM_TICK_TIME, NULL, 0);
if (err < 0)
return err;