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.
Also add definitions for delayed updates if actual trigger tstamp can be only be provided after a delay due to hardware constraints.
Signed-off-by: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com --- include/sound/pcm.h | 2 ++ sound/core/pcm_native.c | 4 +++- 2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/include/sound/pcm.h b/include/sound/pcm.h index 1e7f74a..2641d86 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -281,6 +281,8 @@ 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 */ + bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */ 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 5dc83fb..ae2a93a 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -809,7 +809,8 @@ 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 == 0) + snd_pcm_gettime(runtime, &runtime->trigger_tstamp); } else { snd_pcm_trigger_tstamp(runtime->trigger_master); runtime->trigger_tstamp = runtime->trigger_master->runtime->trigger_tstamp; @@ -978,6 +979,7 @@ 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 = 0; runtime->trigger_master = substream; return 0; }