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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
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44
src/pcm/pcm.c
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@ -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;