Re: [PATCH] ALSA - HDA - Add period time constraint to hda-intel

[Takashi Iwai <tiwai@suse.de>]

At Tue, 24 May 2011 12:15:05 +0800,
Raymond Yau wrote:
> 
> As there is a 10 seconds schedule_timeout in alsa-kernel
> 
> The following error occur when aplay/arecord using a period time
> longer than 10 seconds for for those hda codec which support rate
> lower than 32000 when prealloc = 4096
> 
> ALSA hda_intel.c:1680: azx_pcm_prepare: bufsize=0x1aeb00, format=0x4111
> ...
> ALSA pcm_native.c:1531: playback drain error (DMA or IRQ trouble?)

Wouldn't it be better to fix the PCM timeout itself?
Does the patch below work?


thanks,

Takashi

---
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index abfeff16..a754722 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1756,8 +1756,16 @@ static int wait_for_avail(struct snd_pcm_substream *substream,
 	wait_queue_t wait;
 	int err = 0;
 	snd_pcm_uframes_t avail = 0;
+	long wait_time = 10; /* 10 seconds timeout as default */
 	long tout;
 
+	if (runtime->rate) {
+		long t = (runtime->period_size * 2 + runtime->rate - 1) /
+			runtime->rate;
+		wait_time = max(t, wait_time);
+	}
+	wait_time = msecs_to_jiffies(wait_time * 1000);
+
 	init_waitqueue_entry(&wait, current);
 	add_wait_queue(&runtime->tsleep, &wait);
 	for (;;) {
@@ -1767,7 +1775,7 @@ static int wait_for_avail(struct snd_pcm_substream *substream,
 		}
 		set_current_state(TASK_INTERRUPTIBLE);
 		snd_pcm_stream_unlock_irq(substream);
-		tout = schedule_timeout(msecs_to_jiffies(10000));
+		tout = schedule_timeout(wait_time);
 		snd_pcm_stream_lock_irq(substream);
 		switch (runtime->status->state) {
 		case SNDRV_PCM_STATE_SUSPENDED: