ALSA: pcm: Allow drivers to set R/W wait time. (d64c5cf8) · Commits · 戴 / test

Currently ALSA core blocks userspace for about 10 seconds for PCM R/W IO. This needs to be configurable for modern hardware like DSPs where no pointer update in milliseconds can indicate terminal DSP errors. Add a substream variable to set the wait time in ms. This allows userspace and drivers to recover more quickly from terminal DSP errors. Signed-off-by:

Liam Girdwood <liam.r.girdwood@linux.intel.com> Signed-off-by:

Takashi Iwai <tiwai@suse.de>

include/sound/pcm.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -462,6 +462,7 @@ struct snd_pcm_substream {
		/* -- timer section -- */
		struct snd_timer timer; / timer */
		unsigned timer_running: 1; /* time is running */
		long wait_time; /* time in ms for R/W to wait for avail */
		/* -- next substream -- */
		struct snd_pcm_substream *next;
		/* -- linked substreams -- */

sound/core/pcm_lib.c

+12 −5

Original line number	Diff line number	Diff line
		@@ -1833,13 +1833,20 @@ static int wait_for_avail(struct snd_pcm_substream *substream,
		if (runtime->no_period_wakeup)
		wait_time = MAX_SCHEDULE_TIMEOUT;
		else {
		/* use wait time from substream if available */
		if (substream->wait_time) {
		wait_time = substream->wait_time;
		} else {
		wait_time = 10;

		if (runtime->rate) {
		long t = runtime->period_size * 2 / runtime->rate;
		long t = runtime->period_size * 2 /
		runtime->rate;
		wait_time = max(t, wait_time);
		}
		wait_time = msecs_to_jiffies(wait_time * 1000);
		}
		}

		for (;;) {
		if (signal_pending(current)) {

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