参照元†
- struct snd_pcm_substream *substream
- snd_pcm_uframes_t *availp
返り値†
/*
* Wait until avail_min data becomes available
* Returns a negative error code if any error occurs during operation.
* The available space is stored on availp. When err = 0 and avail = 0
* on the capture stream, it indicates the stream is in DRAINING state.
*/
static int wait_for_avail_min(struct snd_pcm_substream *substream,
snd_pcm_uframes_t *availp)
{
struct snd_pcm_runtime *runtime = substream->runtime;
int is_playback = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
wait_queue_t wait;
int err = 0;
snd_pcm_uframes_t avail = 0;
long tout;
init_waitqueue_entry(&wait, current);
add_wait_queue(&runtime->sleep, &wait);
for (;;) {
if (signal_pending(current)) {
err = -ERESTARTSYS;
break;
}
set_current_state(TASK_INTERRUPTIBLE);
snd_pcm_stream_unlock_irq(substream);
tout = schedule_timeout(msecs_to_jiffies(10000));
snd_pcm_stream_lock_irq(substream);
switch (runtime->status->state) {
case SNDRV_PCM_STATE_SUSPENDED:
err = -ESTRPIPE;
goto _endloop;
case SNDRV_PCM_STATE_XRUN:
err = -EPIPE;
goto _endloop;
case SNDRV_PCM_STATE_DRAINING:
if (is_playback)
err = -EPIPE;
else
avail = 0; /* indicate draining */
goto _endloop;
case SNDRV_PCM_STATE_OPEN:
case SNDRV_PCM_STATE_SETUP:
case SNDRV_PCM_STATE_DISCONNECTED:
err = -EBADFD;
goto _endloop;
}
if (!tout) {
snd_printd("%s write error (DMA or IRQ trouble?)\n",
is_playback ? "playback" : "capture");
err = -EIO;
break;
}
if (is_playback)
avail = snd_pcm_playback_avail(runtime);
else
avail = snd_pcm_capture_avail(runtime);
if (avail >= runtime->control->avail_min)
break;
}
_endloop:
remove_wait_queue(&runtime->sleep, &wait);
*availp = avail;
return err;
}
コメント†