At Sat, 20 May 2006 20:46:34 +0200,
Gerald Grabner wrote:
>
> Takashi Iwai wrote:
> > At Fri, 19 May 2006 21:17:45 +0000 (UTC),
> > Gerald Grabner wrote:
> >> Takashi Iwai <tiwai <at> suse.de> writes:
> >>> At Mon, 15 May 2006 12:06:47 +0200,
> >>> I wrote:
> >>>> At Sat, 13 May 2006 13:06:51 +0200,
> >>>> Gerald Grabner wrote:
> >>>>> Hi,
> >>>>>
> >>>>> I'm experimenting with the ALSA PCM API and was wondering whether
> >>>>> there is a simple way to exit a record loop by stopping the pcm, but
> >>>>> without loosing pending frames.
> >>>>>
> >>>>> Initially, I was thinking of something like this, where I would call
> >>>>> snd_pcm_drop(pcm) from some other thread:
> >>>>>
> >>>>> while ( true )
> >>>>> {
> >>>>> r = snd_pcm_readi (pcm, data, frames);
> >>>>> fwrite (data, 2, 2*r, file);
> >>>>> if ( r != frames )
> >>>>> break;
> >>>>> }
> >>>>>
> >>>>> However, snd_pcm_drain(pcm) doesn't work here; the loop continues.
> >>>>> snd_pcm_drop(pcm) breaks the loop, but pending frames are lost, and
> >>>>> r=-EBADFD.
> >>>>>
> >>>>> Is there an easy way to stop snd_pcm_readi in a way that I can
> >>>>> retrieve the residual frames? Do I need to set any parameters for
> >>>>> that purpose?
> >>>> If you're using hw or plughw, it's likely a bug in alsa-driver.
> >>>> Try the patch below.
> >>> Actually the patch was also wrong. snd_pcm_drain() shouldn't wait for
> >>> the capture streams. So, the patch becomes pretty simple like below.
> >>> I'll commit it to HG repo.
> >>>
> >>> Takashi
> >>>
> >>> diff -r 44d28ed5d3d5 core/pcm_native.c
> >>> --- a/core/pcm_native.c Wed May 17 11:26:39 2006 +0200
> >>> +++ b/core/pcm_native.c Wed May 17 17:07:17 2006 +0200
> >>> <at> <at> -1469,8 +1469,6 <at> <at> static int snd_pcm_drain(
> >> struct snd_pcm_
> >>> }
> >>> }
> >>> up_read(&snd_pcm_link_rwsem);
> >>> - if (! num_drecs)
> >>> - goto _error;
> >>>
> >>> snd_pcm_stream_lock_irq(substream);
> >>> /* resume pause */
> >>
> >> Hi Takashi,
> >>
> >> there seems to be some problem with this patch (the short one). After
> >> recompiling the kernel (and my application), my application doesn't
> >> exit and I can't kill it anymore. The pcm device is kind of lost. See
> >> below for the /var/log/messages entry.
> >
> > Hmm, according the error message below, I suspect it's something
> > different since the patch isn't so intrusive.
> >
> > Could you test again after reverting the patched part?
>
> After recompiling the kernel with the original source, the problem
> disappeared.
OK, could you try the patch below?
thanks,
Takashi
diff -r 18da48cda4cc core/pcm_native.c
--- a/core/pcm_native.c Mon May 22 12:05:42 2006 +0200
+++ b/core/pcm_native.c Mon May 22 12:39:22 2006 +0200
@@ -1381,7 +1381,8 @@ static int snd_pcm_do_drain_init(struct
if (runtime->status->state == SNDRV_PCM_STATE_RUNNING) {
int state = snd_pcm_capture_avail(runtime) > 0 ?
SNDRV_PCM_STATE_DRAINING : SNDRV_PCM_STATE_SETUP;
- snd_pcm_do_stop(substream, state);
+ substream->ops->trigger(substream,
+ SNDRV_PCM_TRIGGER_STOP);
snd_pcm_post_stop(substream, state);
}
}
