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authorMark Brown <broonie@linaro.org>2014-07-08 16:52:32 +0200
committerTakashi Iwai <tiwai@suse.de>2014-07-14 17:35:07 +0200
commit85e4704151677b8fcc5ccfc396071828e9ec1b8e (patch)
treefc0a25f8270fa93315f99c7bda25d18b132222f9
parent035f196bcdc1e9903ed52ad1859dc23d3aa74e72 (diff)
pcm: 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. Reported-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Mark Brown <broonie@linaro.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--include/sound/asound.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/sound/asound.h b/include/sound/asound.h
index 1774a5c3..9061cdd5 100644
--- a/include/sound/asound.h
+++ b/include/sound/asound.h
@@ -457,7 +457,8 @@ struct snd_xfern {
enum {
SNDRV_PCM_TSTAMP_TYPE_GETTIMEOFDAY = 0, /* gettimeofday equivalent */
SNDRV_PCM_TSTAMP_TYPE_MONOTONIC, /* posix_clock_monotonic equivalent */
- SNDRV_PCM_TSTAMP_TYPE_LAST = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC,
+ SNDRV_PCM_TSTAMP_TYPE_MONOTONIC_RAW, /* monotonic_raw (no NTP) */
+ SNDRV_PCM_TSTAMP_TYPE_LAST = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC_RAW,
};
/* channel positions */