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authorMark Brown <broonie@linaro.org>2014-07-08 16:51:49 +0200
committerTakashi Iwai <tiwai@suse.de>2014-07-10 16:58:13 +0200
commit0ac8a52d4541adc284a4f3e8a1f6847236de1d8a (patch)
treee8f02e842c72fc9f9549cffa90198c12e07004e9 /include/sound
parent2408c219df9e7a47680d43ed7877aaaec3feca1b (diff)
downloadlinux-linaro-stable-0ac8a52d4541adc284a4f3e8a1f6847236de1d8a.tar.gz
ALSA: Provide a CLOCK_MONOTONIC_RAW timestamp type
For applications which need to synchronise with external timebases such as broadcast TV applications the kernel monotonic time is not optimal as it includes adjustments from NTP and so may still include discontinuities due to that. A raw monotonic time which does not include any adjustments is available in the kernel from getrawmonotonic() so provide userspace with a new timestamp type SNDRV_PCM_TSTAMP_TYPE_MONOTONIC_RAW which provides timestamps based on this as an option. [dropped tstamp_type assignment code, as it's no longer needed -- tiwai] Reported-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Mark Brown <broonie@linaro.org> Acked-by: Jaroslav Kysela <perex@perex.cz> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'include/sound')
-rw-r--r--include/sound/pcm.h11
1 files changed, 9 insertions, 2 deletions
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index d854fb31c000..6f3e10ca0e32 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -931,10 +931,17 @@ void snd_pcm_timer_done(struct snd_pcm_substream *substream);
static inline void snd_pcm_gettime(struct snd_pcm_runtime *runtime,
struct timespec *tv)
{
- if (runtime->tstamp_type == SNDRV_PCM_TSTAMP_TYPE_MONOTONIC)
+ switch (runtime->tstamp_type) {
+ case SNDRV_PCM_TSTAMP_TYPE_MONOTONIC:
ktime_get_ts(tv);
- else
+ break;
+ case SNDRV_PCM_TSTAMP_TYPE_MONOTONIC_RAW:
+ getrawmonotonic(tv);
+ break;
+ default:
getnstimeofday(tv);
+ break;
+ }
}
/*