At Mon, 22 May 2006 12:41:45 +0200,
I wrote:
>
> [1 <text/plain; US-ASCII (7bit)>]
> 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?
In case it still doesn't fix -- please elaborate what your app
actually does. Or even better a small test code.
I still don't figure out how can it happen.
thanks,
Takashi
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