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[ALSA] Use posix clock monotonic for PCM and timer timestamps

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We need an accurate and continuous (monotonic) time sources to do
accurate synchronization among more timing sources. This patch allows
to enable monotonic timestamps for ALSA PCM devices and enables monotonic
timestamps for ALSA timer devices.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Jaroslav Kysela
2007-12-13 10:19:42 +01:00
parent 25543fa785
commit b751eef1fd
5 changed files with 52 additions and 11 deletions
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10
include/sound/asound.h
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@@ -138,7 +138,7 @@ enum {
* *
*****************************************************************************/
#define SNDRV_PCM_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 8)
#define SNDRV_PCM_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 9)
typedef unsigned long snd_pcm_uframes_t;
typedef signed long snd_pcm_sframes_t;
@@ -434,10 +434,16 @@ struct snd_xfern {
snd_pcm_uframes_t frames;
};
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,
};
enum {
SNDRV_PCM_IOCTL_PVERSION = _IOR('A', 0x00, int),
SNDRV_PCM_IOCTL_INFO = _IOR('A', 0x01, struct snd_pcm_info),
SNDRV_PCM_IOCTL_TSTAMP = _IOW('A', 0x02, int),
SNDRV_PCM_IOCTL_TTSTAMP = _IOW('A', 0x03, int),
SNDRV_PCM_IOCTL_HW_REFINE = _IOWR('A', 0x10, struct snd_pcm_hw_params),
SNDRV_PCM_IOCTL_HW_PARAMS = _IOWR('A', 0x11, struct snd_pcm_hw_params),
SNDRV_PCM_IOCTL_HW_FREE = _IO('A', 0x12),