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pcm: improve handling for snd_pcm_wait()

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The snd_pcm_wait() function is called also internally from
the various plugins to wait for the drain with -1 and from i/o
routines in pcm.c.

Define two special negative timeout values to distinguish the
drain and i/o wait and calculate the maximal timeout according
the wait place.

Fixes: https://github.com/alsa-project/alsa-lib/issues/228
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Jaroslav Kysela 2023-05-02 16:56:49 +02:00
parent 1de6f99c7d
commit e2d9e41174
9 changed files with 55 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

7
include/pcm.h
View file

@ -498,6 +498,13 @@ typedef union _snd_pcm_sync_id {
unsigned int id32[4];
} snd_pcm_sync_id_t;
/** Infinite wait for snd_pcm_wait() */
#define SND_PCM_WAIT_INFINITE (-1)
/** Wait for next i/o in snd_pcm_wait() */
#define SND_PCM_WAIT_IO (-10001)
/** Wait for drain in snd_pcm_wait() */
#define SND_PCM_WAIT_DRAIN (-10002)
/** #SND_PCM_TYPE_METER scope handle */
typedef struct _snd_pcm_scope snd_pcm_scope_t;

44
src/pcm/pcm.c
View file

@ -2834,7 +2834,8 @@ int snd_pcm_open_named_slave(snd_pcm_t **pcmp, const char *name,
* \brief Wait for a PCM to become ready
* \param pcm PCM handle
* \param timeout maximum time in milliseconds to wait,
* a negative value means infinity
* a -1 value means infinity (SND_PCM_WAIT_INFINITE),
* see also SND_PCM_WAIT_IO and SND_PCM_WAIT_DRAIN
* \return a positive value on success otherwise a negative error code
* (-EPIPE for the xrun and -ESTRPIPE for the suspended status,
* others for general errors)
@ -2869,6 +2870,37 @@ int __snd_pcm_wait_in_lock(snd_pcm_t *pcm, int timeout)
return snd_pcm_wait_nocheck(pcm, timeout);
}
static int __snd_pcm_wait_io_timeout(snd_pcm_t *pcm)
{
int timeout;
/* period size is the time boundary */
timeout = (pcm->period_size * 1000ULL) / pcm->rate;
/* should not happen */
if (timeout < 0)
timeout = 0;
/* add extra time of 200 milliseconds */
timeout += 200;
return timeout;
}
static int __snd_pcm_wait_drain_timeout(snd_pcm_t *pcm)
{
int timeout;
/* for capture, there's no reason to wait, just one iteration */
if (snd_pcm_stream(pcm) == SND_PCM_STREAM_CAPTURE)
return 0;
/* result is in milliseconds */
timeout = (snd_pcm_mmap_playback_delay(pcm) * 1000LL) / pcm->rate;
/* should not happen */
if (timeout < 0)
timeout = 0;
/* add extra time of 200 milliseconds */
timeout += 200;
return timeout;
}
/*
* like snd_pcm_wait() but doesn't check mmap_avail before calling poll()
*
@ -2895,6 +2927,12 @@ int snd_pcm_wait_nocheck(snd_pcm_t *pcm, int timeout)
SNDMSG("invalid poll descriptors %d\n", err);
return -EIO;
}
if (timeout == SND_PCM_WAIT_IO)
timeout = __snd_pcm_wait_io_timeout(pcm);
else if (timeout == SND_PCM_WAIT_DRAIN)
timeout = __snd_pcm_wait_drain_timeout(pcm);
else if (timeout < -1)
SNDMSG("invalid snd_pcm_wait timeout argument %d\n", timeout);
do {
__snd_pcm_unlock(pcm->fast_op_arg);
err_poll = poll(pfd, npfds, timeout);
@ -7525,7 +7563,7 @@ snd_pcm_sframes_t snd_pcm_read_areas(snd_pcm_t *pcm, const snd_pcm_channel_area_
goto _end;
}
err = __snd_pcm_wait_in_lock(pcm, -1);
err = __snd_pcm_wait_in_lock(pcm, SND_PCM_WAIT_IO);
if (err < 0)
break;
goto _again;
@ -7594,7 +7632,7 @@ snd_pcm_sframes_t snd_pcm_write_areas(snd_pcm_t *pcm, const snd_pcm_channel_area
goto _end;
}
err = snd_pcm_wait_nocheck(pcm, -1);
err = snd_pcm_wait_nocheck(pcm, SND_PCM_WAIT_IO);
if (err < 0)
break;
goto _again;

2
src/pcm/pcm_dmix.c
View file

@ -623,7 +623,7 @@ static int __snd_pcm_dmix_drain(snd_pcm_t *pcm)
if (dmix->state == SND_PCM_STATE_DRAINING) {
snd_pcm_dmix_sync_area(pcm);
if ((pcm->mode & SND_PCM_NONBLOCK) == 0) {
snd_pcm_wait_nocheck(pcm, -1);
snd_pcm_wait_nocheck(pcm, SND_PCM_WAIT_DRAIN);
snd_pcm_direct_clear_timer_queue(dmix); /* force poll to wait */
}

2
src/pcm/pcm_dshare.c
View file

@ -400,7 +400,7 @@ static int __snd_pcm_dshare_drain(snd_pcm_t *pcm)
}
if (dshare->state == SND_PCM_STATE_DRAINING) {
snd_pcm_dshare_sync_area(pcm);
snd_pcm_wait_nocheck(pcm, -1);
snd_pcm_wait_nocheck(pcm, SND_PCM_WAIT_DRAIN);
snd_pcm_direct_clear_timer_queue(dshare); /* force poll to wait */
switch (snd_pcm_state(dshare->spcm)) {

2
src/pcm/pcm_dsnoop.c
View file

@ -301,7 +301,7 @@ static int __snd_pcm_dsnoop_drain(snd_pcm_t *pcm)
break;
if (pcm->mode & SND_PCM_NONBLOCK)
return -EAGAIN;
__snd_pcm_wait_in_lock(pcm, -1);
__snd_pcm_wait_in_lock(pcm, SND_PCM_WAIT_DRAIN);
}
pcm->stop_threshold = stop_threshold;
return snd_pcm_dsnoop_drop(pcm);

2
src/pcm/pcm_ioplug.c
View file

@ -522,7 +522,7 @@ static int ioplug_drain_via_poll(snd_pcm_t *pcm)
/* in non-blocking mode, let application to poll() by itself */
if (io->data->nonblock)
return -EAGAIN;
if (snd_pcm_wait_nocheck(pcm, -1) < 0)
if (snd_pcm_wait_nocheck(pcm, SND_PCM_WAIT_DRAIN) < 0)
break;
}

2
src/pcm/pcm_rate.c
View file

@ -1146,7 +1146,7 @@ static int snd_pcm_rate_drain(snd_pcm_t *pcm)
snd_pcm_uframes_t psize, spsize;
int err;
err = __snd_pcm_wait_in_lock(rate->gen.slave, -1);
err = __snd_pcm_wait_in_lock(rate->gen.slave, SND_PCM_WAIT_DRAIN);
if (err < 0)
break;
if (size > pcm->period_size) {

2
src/pcm/pcm_share.c
View file

@ -1194,7 +1194,7 @@ static int snd_pcm_share_drain(snd_pcm_t *pcm)
_snd_pcm_share_update(pcm);
Pthread_mutex_unlock(&slave->mutex);
if (!(pcm->mode & SND_PCM_NONBLOCK))
snd_pcm_wait(pcm, -1);
snd_pcm_wait(pcm, SND_PCM_WAIT_DRAIN);
return 0;
default:
assert(0);

2
src/pcm/pcm_shm.c
View file

@ -495,7 +495,7 @@ static int snd_pcm_shm_drain(snd_pcm_t *pcm)
if (err < 0)
return err;
if (!(pcm->mode & SND_PCM_NONBLOCK))
snd_pcm_wait(pcm, -1);
snd_pcm_wait(pcm, SND_PCM_WAIT_DRAIN);
return err;
}