Hi all,
I posted this V2 patch a few weeks ago, it provoked a little chat but not much else :)
It probably looked like dumped it on the list just before the holiday - that's what happened, and it was a pretty crap move. There was some pressure at this end, and it was all a bit awkward ;) Anyways, I know I didn't handle that the right way.
So, in the spirit of a brighter 2015, I'm back to get start_at functionality merged! For fun and profit, etc.
The second patch was much better than the first (naturally :P), but didn't feature too much in the way of documentation and explanation, which was a big misstep.
If no-one has any major objections, I'll amend the V2 patch to include a clearer explanation of the implementation, how to use start_at, and why it should be merged with open arms! ;)
If you have any further suggestions about how to get code like this merged, I'm all ears.
Thanks, Tim
On 17/12/14 17:27, Tim Cussins wrote:
Add notion of TSTAMP_CLASS (SYSTEM/AUDIO) as per Pierre's suggestion. Add snd_pcm_start_at()
Signed-off-by: Tim Cussins timcussins@eml.cc
diff --git a/include/pcm.h b/include/pcm.h index 0655e7f..c57edca 100644 --- a/include/pcm.h +++ b/include/pcm.h @@ -323,13 +323,25 @@ typedef enum _snd_pcm_tstamp { SND_PCM_TSTAMP_LAST = SND_PCM_TSTAMP_ENABLE } snd_pcm_tstamp_t;
+typedef enum _snd_pcm_tstamp_class {
- SND_PCM_TSTAMP_CLASS_SYSTEM = 0,
- SND_PCM_TSTAMP_CLASS_AUDIO,
- SND_PCM_TSTAMP_CLASS_LAST = SND_PCM_TSTAMP_CLASS_AUDIO,
+} snd_pcm_tstamp_class_t;
- typedef enum _snd_pcm_tstamp_type { SND_PCM_TSTAMP_TYPE_GETTIMEOFDAY = 0, /** gettimeofday equivalent */
- SND_PCM_TSTAMP_TYPE_MONOTONIC, /** posix_clock_monotonic equivalent */
- SND_PCM_TSTAMP_TYPE_MONOTONIC, /** posix_clock_monotonic equivalent */ SND_PCM_TSTAMP_TYPE_MONOTONIC_RAW, /** monotonic_raw (no NTP) */ SND_PCM_TSTAMP_TYPE_LAST = SND_PCM_TSTAMP_TYPE_MONOTONIC_RAW, } snd_pcm_tstamp_type_t;
+typedef enum _snd_pcm_audio_tstamp_type {
- SND_PCM_AUDIO_TSTAMP_TYPE_DEFAULT = 0,
- SND_PCM_AUDIO_TSTAMP_TYPE_LINK,
- SND_PCM_AUDIO_TSTAMP_TYPE_LAST = SND_PCM_AUDIO_TSTAMP_TYPE_LINK,
+} snd_pcm_audio_tstamp_t;
- /** Unsigned frames quantity */ typedef unsigned long snd_pcm_uframes_t; /** Signed frames quantity */
@@ -478,6 +490,7 @@ int snd_pcm_prepare(snd_pcm_t *pcm); int snd_pcm_reset(snd_pcm_t *pcm); int snd_pcm_status(snd_pcm_t *pcm, snd_pcm_status_t *status); int snd_pcm_start(snd_pcm_t *pcm); +int snd_pcm_start_at(snd_pcm_t *pcm, snd_pcm_tstamp_class_t tstamp_class, int tstamp_type, const snd_htimestamp_t* start_time); int snd_pcm_drop(snd_pcm_t *pcm); int snd_pcm_drain(snd_pcm_t *pcm); int snd_pcm_pause(snd_pcm_t *pcm, int enable); diff --git a/include/sound/asound.h b/include/sound/asound.h index 1f23cd6..1592160 100644 --- a/include/sound/asound.h +++ b/include/sound/asound.h @@ -466,12 +466,30 @@ struct snd_xfern { };
enum {
- SNDRV_PCM_TSTAMP_CLASS_SYSTEM = 0,
- SNDRV_PCM_TSTAMP_CLASS_AUDIO,
- SNDRV_PCM_TSTAMP_CLASS_LAST = SNDRV_PCM_TSTAMP_CLASS_AUDIO,
+};
+enum { SNDRV_PCM_TSTAMP_TYPE_GETTIMEOFDAY = 0, /* gettimeofday equivalent */ SNDRV_PCM_TSTAMP_TYPE_MONOTONIC, /* posix_clock_monotonic equivalent */
- SNDRV_PCM_TSTAMP_TYPE_MONOTONIC_RAW, /* monotonic_raw (no NTP) */
- SNDRV_PCM_TSTAMP_TYPE_MONOTONIC_RAW, /* monotonic_raw (no NTP) */ SNDRV_PCM_TSTAMP_TYPE_LAST = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC_RAW, };
+enum {
- SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT = 0,
- SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK,
- SNDRV_PCM_AUDIO_TSTAMP_TYPE_LAST = SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK,
+};
+struct snd_start_at {
- int tstamp_class;
- int tstamp_type;
- struct timespec start_time;
+};
- /* channel positions */ enum { SNDRV_CHMAP_UNKNOWN = 0,
@@ -550,6 +568,8 @@ enum { #define SNDRV_PCM_IOCTL_READN_FRAMES _IOR('A', 0x53, struct snd_xfern) #define SNDRV_PCM_IOCTL_LINK _IOW('A', 0x60, int) #define SNDRV_PCM_IOCTL_UNLINK _IO('A', 0x61) +#define SNDRV_PCM_IOCTL_START_AT _IOW('A', 0x62, struct snd_start_at)
/*****************************************************************************
*diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c index baa47c7..40a4689 100644 --- a/src/pcm/pcm.c +++ b/src/pcm/pcm.c @@ -1085,6 +1085,37 @@ int snd_pcm_start(snd_pcm_t *pcm) }
/**
- \brief Start a PCM at a specified point in the future
- \param pcm PCM handle
- \param tstamp_class specifies the class of tstamp_type
- \param tstamp_type specifies the clock with which to interpret \p start_time
- \param start_time Absolute time at which to start the stream
- \return 0 on success otherwise a negative error code
- \retval -ENOSYS operation not supported for the current timestamp type
- \retval -EINVAL timespec, tstamp_class or tstamp_type is invalid
- \retval -ETIME requested start_time cannot be satisfied
- This method is non-blocking: It establishes an appropriate timer in the kernel
- that will start the stream on expiry.
- The timer is unconditionally cancelled upon any \a attempt to change the stream
- state e.g. drop, drain, start, start_at.
- */
+int snd_pcm_start_at(snd_pcm_t *pcm, snd_pcm_tstamp_class_t tstamp_class, int tstamp_type, const snd_htimestamp_t *start_time) +{
- assert(pcm);
- assert(start_time);
- if (CHECK_SANITY(! pcm->setup)) {
SNDMSG("PCM not set up");return -EIO;- }
- if (pcm->fast_ops->start_at) {
return pcm->fast_ops->start_at(pcm->fast_op_arg, tstamp_class, tstamp_type, start_time);- }
- return -EINVAL;
+}
+/**
- \brief Stop a PCM dropping pending frames
- \param pcm PCM handle
- \return 0 on success otherwise a negative error code
diff --git a/src/pcm/pcm_hw.c b/src/pcm/pcm_hw.c index c34b766..0190787 100644 --- a/src/pcm/pcm_hw.c +++ b/src/pcm/pcm_hw.c @@ -620,6 +620,26 @@ static int snd_pcm_hw_start(snd_pcm_t *pcm) return 0; }
+static int snd_pcm_hw_start_at(snd_pcm_t *pcm, snd_pcm_tstamp_class_t tstamp_class, int tstamp_type, const snd_htimestamp_t *start_time) +{
- snd_pcm_hw_t *hw = pcm->private_data;
- int err;
- struct snd_start_at start_at = {
.tstamp_class = tstamp_class,.tstamp_type = tstamp_type,.start_time = *start_time- };
- sync_ptr(hw, 0);
- if (ioctl(hw->fd, SNDRV_PCM_IOCTL_START_AT, &start_at) < 0) {
err = -errno;SYSMSG("SNDRV_PCM_IOCTL_START_AT failed (%i)", err);return err;- }
- return 0;
+}
- static int snd_pcm_hw_drop(snd_pcm_t *pcm) { snd_pcm_hw_t *hw = pcm->private_data;
@@ -1336,6 +1356,7 @@ static const snd_pcm_fast_ops_t snd_pcm_hw_fast_ops = { .prepare = snd_pcm_hw_prepare, .reset = snd_pcm_hw_reset, .start = snd_pcm_hw_start,
- .start_at = snd_pcm_hw_start_at, .drop = snd_pcm_hw_drop, .drain = snd_pcm_hw_drain, .pause = snd_pcm_hw_pause,
diff --git a/src/pcm/pcm_local.h b/src/pcm/pcm_local.h index 394505f..5cdfd3a 100644 --- a/src/pcm/pcm_local.h +++ b/src/pcm/pcm_local.h @@ -154,6 +154,7 @@ typedef struct { int (*prepare)(snd_pcm_t *pcm); int (*reset)(snd_pcm_t *pcm); int (*start)(snd_pcm_t *pcm);
- int (*start_at)(snd_pcm_t *pcm, snd_pcm_tstamp_class_t tstamp_class, int tstamp_type, const snd_htimestamp_t *start_time); int (*drop)(snd_pcm_t *pcm); int (*drain)(snd_pcm_t *pcm); int (*pause)(snd_pcm_t *pcm, int enable);