Re: [alsa-devel] [PATCH v4 03/10] ALSA: hda: read trigger_timestamp immediately after starting DMA

At Fri, 30 Jan 2015 17:55:56 -0600, Pierre-Louis Bossart wrote:

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

sound/pci/hda/hda_controller.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/sound/pci/hda/hda_controller.c b/sound/pci/hda/hda_controller.c index 0cfc9c8..271f86e 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 = 1;
  

Better to use "true" for boolean.

Takashi