summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>2015-02-06 15:55:51 -0600
committerTakashi Iwai <tiwai@suse.de>2015-02-09 16:01:53 +0100
commit2b79d7a6bf341ebeffb85fc2b3577d0cfa810c49 (patch)
tree164985dd74d92ed3563be5d52f656e1d7dd9444f
parent0d59b814353d397ff5d00ac33acd536030252a98 (diff)
ALSA: pcm: allow for trigger_tstamp snapshot in .trigger
Don't use generic snapshot of trigger_tstamp if low-level driver or hardware can get a more precise value for better audio/system time synchronization. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--include/sound/pcm.h1
-rw-r--r--sound/core/pcm_native.c4
2 files changed, 4 insertions, 1 deletions
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index 07299b295233..c0ddb7e69c28 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -285,6 +285,7 @@ struct snd_pcm_runtime {
/* -- Status -- */
struct snd_pcm_substream *trigger_master;
struct timespec trigger_tstamp; /* trigger timestamp */
+ bool trigger_tstamp_latched; /* trigger timestamp latched in low-level driver/hardware */
int overrange;
snd_pcm_uframes_t avail_max;
snd_pcm_uframes_t hw_ptr_base; /* Position at buffer restart */
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 4ecd35fbfe3f..b03a638b420c 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -810,7 +810,8 @@ static void snd_pcm_trigger_tstamp(struct snd_pcm_substream *substream)
if (runtime->trigger_master == NULL)
return;
if (runtime->trigger_master == substream) {
- snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
+ if (!runtime->trigger_tstamp_latched)
+ snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
} else {
snd_pcm_trigger_tstamp(runtime->trigger_master);
runtime->trigger_tstamp = runtime->trigger_master->runtime->trigger_tstamp;
@@ -979,6 +980,7 @@ static int snd_pcm_pre_start(struct snd_pcm_substream *substream, int state)
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
!snd_pcm_playback_data(substream))
return -EPIPE;
+ runtime->trigger_tstamp_latched = false;
runtime->trigger_master = substream;
return 0;
}