From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Date: Fri, 6 Feb 2015 21:55:50 +0000 (-0600)
Subject: ALSA: pcm: don't override timestamp unconditionally
X-Git-Tag: v4.0-rc1~129^2~11
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=0d59b814353d397ff5d00ac33acd536030252a98;p=linux.git

ALSA: pcm: don't override timestamp unconditionally

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@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 932234d87927..4ecd35fbfe3f 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -720,8 +720,11 @@ 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;