[alsa-devel] [PATCH RFC 1/9] ALSA: core: don't override timestamp unconditionally

[Pierre-Louis Bossart]

timestamp in RUNNING mode is already taken in update_hw_ptr routine,
getting a new timestamp introduces offset between hw_ptr, audio_tstamp
and system time

Add else condition to read timestamp as fallback and only when
enabled

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---
 sound/core/pcm_native.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 095d957..5dc83fb 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -719,8 +719,11 @@ int snd_pcm_status(struct snd_pcm_substream *substream,
 				runtime->status->audio_tstamp;
 			goto _tstamp_end;
 		}
+	} else {
+		/* get tstamp only in fallback mode and only if enabled */
+		if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE)
+			snd_pcm_gettime(runtime, &status->tstamp);
 	}
-	snd_pcm_gettime(runtime, &status->tstamp);
  _tstamp_end:
 	status->appl_ptr = runtime->control->appl_ptr;
 	status->hw_ptr = runtime->status->hw_ptr;
-- 
2.1.0