[alsa-devel] Loopback interface: suspend/resume leads to a kernel crash

[Takashi Iwai]

At Fri, 01 Feb 2013 15:48:53 +0100,
Takashi Iwai wrote:
> 
> At Thu, 31 Jan 2013 21:09:13 +0100,
> El boulangero wrote:
> > 
> > Hi,
> > 
> > I use the loopback device all the time. It works pretty good, except
> > when I suspend my computer to RAM. On resume, I've got a kernel call
> > trace.
> 
> Which kernel are you using?  Some races in aloop driver have been
> fixed in 3.7 kernel.

If the problem is still seen on 3.6 kernel, try the patch below.
Let me know if it fixes the problem.


Takashi

---
diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c
index 3d82232..64d5347 100644
--- a/sound/drivers/aloop.c
+++ b/sound/drivers/aloop.c
@@ -286,12 +286,14 @@ static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 			loopback_active_notify(dpcm);
 		break;
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
 		spin_lock(&cable->lock);	
 		cable->pause |= stream;
 		loopback_timer_stop(dpcm);
 		spin_unlock(&cable->lock);
 		break;
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+	case SNDRV_PCM_TRIGGER_RESUME:
 		spin_lock(&cable->lock);
 		dpcm->last_jiffies = jiffies;
 		cable->pause &= ~stream;
@@ -563,7 +565,8 @@ static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 static struct snd_pcm_hardware loopback_pcm_hardware =
 {
 	.info =		(SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
-			 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE),
+			 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
+			 SNDRV_PCM_INFO_RESUME),
 	.formats =	(SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 			 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 			 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),