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ALSA: Add extra delay count in PCM

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Added runtime->delay field to adjust the delayed samples for snd_pcm_delay().
Typically a hardware FIFO length is stored in this field, so that the
extra delay between hwptr and applptr can be computed.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2008-10-13 03:07:14 +02:00
parent 091438dd56
commit 4bbe1ddf89
2 changed files with 6 additions and 3 deletions
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1
include/sound/pcm.h
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@ -270,6 +270,7 @@ struct snd_pcm_runtime {
snd_pcm_uframes_t hw_ptr_base; /* Position at buffer restart */
snd_pcm_uframes_t hw_ptr_interrupt; /* Position at interrupt time */
unsigned long hw_ptr_jiffies; /* Time when hw_ptr is updated */
snd_pcm_sframes_t delay; /* extra delay; typically FIFO size */
/* -- HW params -- */
snd_pcm_access_t access; /* access mode */

8
sound/core/pcm_native.c
View File

@ -587,14 +587,15 @@ int snd_pcm_status(struct snd_pcm_substream *substream,
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
status->avail = snd_pcm_playback_avail(runtime);
if (runtime->status->state == SNDRV_PCM_STATE_RUNNING ||
runtime->status->state == SNDRV_PCM_STATE_DRAINING)
runtime->status->state == SNDRV_PCM_STATE_DRAINING) {
status->delay = runtime->buffer_size - status->avail;
else
status->delay += runtime->delay;
} else
status->delay = 0;
} else {
status->avail = snd_pcm_capture_avail(runtime);
if (runtime->status->state == SNDRV_PCM_STATE_RUNNING)
status->delay = status->avail;
status->delay = status->avail + runtime->delay;
else
status->delay = 0;
}
@ -2404,6 +2405,7 @@ static int snd_pcm_delay(struct snd_pcm_substream *substream,
n = snd_pcm_playback_hw_avail(runtime);
else
n = snd_pcm_capture_avail(runtime);
n += runtime->delay;
break;
case SNDRV_PCM_STATE_XRUN:
err = -EPIPE;