diff options
| -rw-r--r-- | include/tinyalsa/asoundlib.h | 3 | ||||
| -rw-r--r-- | pcm.c | 11 |
2 files changed, 14 insertions, 0 deletions
diff --git a/include/tinyalsa/asoundlib.h b/include/tinyalsa/asoundlib.h index 3d20b94..5c08577 100644 --- a/include/tinyalsa/asoundlib.h +++ b/include/tinyalsa/asoundlib.h @@ -55,6 +55,7 @@ struct pcm; * second call to pcm_write will attempt to * restart the stream. */ +#define PCM_MONOTONIC 0x00000008 /* see pcm_get_htimestamp */ /* PCM runtime states */ #define PCM_STATE_OPEN 0 @@ -166,6 +167,8 @@ unsigned int pcm_bytes_to_frames(struct pcm *pcm, unsigned int bytes); unsigned int pcm_get_latency(struct pcm *pcm); /* Returns available frames in pcm buffer and corresponding time stamp. + * The clock is CLOCK_MONOTONIC if flag PCM_MONOTONIC was specified in pcm_open, + * otherwise the clock is CLOCK_REALTIME. * For an input stream, frames available are frames ready for the * application to read. * For an output stream, frames available are the number of empty frames available @@ -719,6 +719,17 @@ struct pcm *pcm_open(unsigned int card, unsigned int device, goto fail; } +#ifdef SNDRV_PCM_IOCTL_TTSTAMP + if (pcm->flags & PCM_MONOTONIC) { + int arg = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC; + rc = ioctl(pcm->fd, SNDRV_PCM_IOCTL_TTSTAMP, &arg); + if (rc < 0) { + oops(pcm, rc, "cannot set timestamp type"); + goto fail; + } + } +#endif + pcm->underruns = 0; return pcm; |