From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Date: Fri, 6 Feb 2015 21:55:52 +0000 (-0600)
Subject: ALSA: hda: read trigger_timestamp immediately after starting DMA
X-Git-Tag: firefly_0821_release~176^2~2367^2~9
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ed610af86a717152be5aa5e29410c5183992b4f2;p=firefly-linux-kernel-4.4.55.git

ALSA: hda: read trigger_timestamp immediately after starting DMA

Make sure wallclock counter and trigger timestamp are read very
close to each other for better alignment.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

diff --git a/sound/pci/hda/hda_controller.c b/sound/pci/hda/hda_controller.c
index 27dcb142f596..dfcb5e929f9f 100644
--- a/sound/pci/hda/hda_controller.c
+++ b/sound/pci/hda/hda_controller.c
@@ -657,6 +657,9 @@ static int azx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 		azx_writel(chip, SSYNC, azx_readl(chip, SSYNC) & ~sbits);
 	if (start) {
 		azx_timecounter_init(substream, 0, 0);
+		snd_pcm_gettime(substream->runtime, &substream->runtime->trigger_tstamp);
+		substream->runtime->trigger_tstamp_latched = true;
+
 		if (nsync > 1) {
 			cycle_t cycle_last;