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ALSA: core: add .get_time_info
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Introduce more generic .get_time_info to retrieve
system timestamp and audio timestamp in single routine.
Backwards compatibility is preserved with same functionality
as with .wall_clock method (to be removed in following commits
to avoid breaking git bisect)

Signed-off-by: Pierre-Louis Bossart <[email protected]>
Signed-off-by: Takashi Iwai <[email protected]>
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@plbossart @tiwai
plbossart authored and tiwai committed Feb 20, 2015
1 parent 5442a73 commit 3179f62
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Showing 3 changed files with 87 additions and 29 deletions.
4 changes: 4 additions & 0 deletions include/sound/pcm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,10 @@ struct snd_pcm_ops {
snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *substream);
int (*wall_clock)(struct snd_pcm_substream *substream,
struct timespec *audio_ts);
int (*get_time_info)(struct snd_pcm_substream *substream,
struct timespec *system_ts, struct timespec *audio_ts,
struct snd_pcm_audio_tstamp_config *audio_tstamp_config,
struct snd_pcm_audio_tstamp_report *audio_tstamp_report);
int (*copy)(struct snd_pcm_substream *substream, int channel,
snd_pcm_uframes_t pos,
void __user *buf, snd_pcm_uframes_t count);
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88 changes: 59 additions & 29 deletions sound/core/pcm_lib.c
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Original file line number Diff line number Diff line change
Expand Up @@ -232,6 +232,49 @@ int snd_pcm_update_state(struct snd_pcm_substream *substream,
return 0;
}

static void update_audio_tstamp(struct snd_pcm_substream *substream,
struct timespec *curr_tstamp,
struct timespec *audio_tstamp)
{
struct snd_pcm_runtime *runtime = substream->runtime;
u64 audio_frames, audio_nsecs;
struct timespec driver_tstamp;

if (runtime->tstamp_mode != SNDRV_PCM_TSTAMP_ENABLE)
return;

if (!(substream->ops->get_time_info) ||
(runtime->audio_tstamp_report.actual_type ==
SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT)) {

/*
* provide audio timestamp derived from pointer position
* add delay only if requested
*/

audio_frames = runtime->hw_ptr_wrap + runtime->status->hw_ptr;

if (runtime->audio_tstamp_config.report_delay) {
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
audio_frames -= runtime->delay;
else
audio_frames += runtime->delay;
}
audio_nsecs = div_u64(audio_frames * 1000000000LL,
runtime->rate);
*audio_tstamp = ns_to_timespec(audio_nsecs);
}
runtime->status->audio_tstamp = *audio_tstamp;
runtime->status->tstamp = *curr_tstamp;

/*
* re-take a driver timestamp to let apps detect if the reference tstamp
* read by low-level hardware was provided with a delay
*/
snd_pcm_gettime(substream->runtime, (struct timespec *)&driver_tstamp);
runtime->driver_tstamp = driver_tstamp;
}

static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
unsigned int in_interrupt)
{
Expand All @@ -256,11 +299,18 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
pos = substream->ops->pointer(substream);
curr_jiffies = jiffies;
if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) {
snd_pcm_gettime(runtime, (struct timespec *)&curr_tstamp);

if ((runtime->hw.info & SNDRV_PCM_INFO_HAS_WALL_CLOCK) &&
(substream->ops->wall_clock))
substream->ops->wall_clock(substream, &audio_tstamp);
if ((substream->ops->get_time_info) &&
(runtime->audio_tstamp_config.type_requested != SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT)) {
substream->ops->get_time_info(substream, &curr_tstamp,
&audio_tstamp,
&runtime->audio_tstamp_config,
&runtime->audio_tstamp_report);

/* re-test in case tstamp type is not supported in hardware and was demoted to DEFAULT */
if (runtime->audio_tstamp_report.actual_type == SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT)
snd_pcm_gettime(runtime, (struct timespec *)&curr_tstamp);
} else
snd_pcm_gettime(runtime, (struct timespec *)&curr_tstamp);
}

if (pos == SNDRV_PCM_POS_XRUN) {
Expand Down Expand Up @@ -403,8 +453,10 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
}

no_delta_check:
if (runtime->status->hw_ptr == new_hw_ptr)
if (runtime->status->hw_ptr == new_hw_ptr) {
update_audio_tstamp(substream, &curr_tstamp, &audio_tstamp);
return 0;
}

if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
runtime->silence_size > 0)
Expand All @@ -426,30 +478,8 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
snd_BUG_ON(crossed_boundary != 1);
runtime->hw_ptr_wrap += runtime->boundary;
}
if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) {
runtime->status->tstamp = curr_tstamp;

if (!(runtime->hw.info & SNDRV_PCM_INFO_HAS_WALL_CLOCK)) {
/*
* no wall clock available, provide audio timestamp
* derived from pointer position+delay
*/
u64 audio_frames, audio_nsecs;

if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
audio_frames = runtime->hw_ptr_wrap
+ runtime->status->hw_ptr
- runtime->delay;
else
audio_frames = runtime->hw_ptr_wrap
+ runtime->status->hw_ptr
+ runtime->delay;
audio_nsecs = div_u64(audio_frames * 1000000000LL,
runtime->rate);
audio_tstamp = ns_to_timespec(audio_nsecs);
}
runtime->status->audio_tstamp = audio_tstamp;
}
update_audio_tstamp(substream, &curr_tstamp, &audio_tstamp);

return snd_pcm_update_state(substream, runtime);
}
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24 changes: 24 additions & 0 deletions sound/core/pcm_native.c
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Original file line number Diff line number Diff line change
Expand Up @@ -707,6 +707,23 @@ int snd_pcm_status(struct snd_pcm_substream *substream,
struct snd_pcm_runtime *runtime = substream->runtime;

snd_pcm_stream_lock_irq(substream);

snd_pcm_unpack_audio_tstamp_config(status->audio_tstamp_data,
&runtime->audio_tstamp_config);

/* backwards compatible behavior */
if (runtime->audio_tstamp_config.type_requested ==
SNDRV_PCM_AUDIO_TSTAMP_TYPE_COMPAT) {
if (runtime->hw.info & SNDRV_PCM_INFO_HAS_WALL_CLOCK)
runtime->audio_tstamp_config.type_requested =
SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK;
else
runtime->audio_tstamp_config.type_requested =
SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT;
runtime->audio_tstamp_report.valid = 0;
} else
runtime->audio_tstamp_report.valid = 1;

status->state = runtime->status->state;
status->suspended_state = runtime->status->suspended_state;
if (status->state == SNDRV_PCM_STATE_OPEN)
Expand All @@ -716,8 +733,15 @@ int snd_pcm_status(struct snd_pcm_substream *substream,
snd_pcm_update_hw_ptr(substream);
if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) {
status->tstamp = runtime->status->tstamp;
status->driver_tstamp = runtime->driver_tstamp;
status->audio_tstamp =
runtime->status->audio_tstamp;
if (runtime->audio_tstamp_report.valid == 1)
/* backwards compatibility, no report provided in COMPAT mode */
snd_pcm_pack_audio_tstamp_report(&status->audio_tstamp_data,
&status->audio_tstamp_accuracy,
&runtime->audio_tstamp_report);

goto _tstamp_end;
}
} else {
Expand Down

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