From: Mark Brown broonie@linaro.org
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 --- include/sound/asound.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/sound/asound.h b/include/sound/asound.h index 1774a5c3ef10..9061cdd5b69f 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 */