On Fri, 16 Nov 2007, Takashi Iwai wrote:
> At Fri, 16 Nov 2007 11:41:51 +0100 (CET),
> Jaroslav Kysela wrote:
> >
> > On Fri, 16 Nov 2007, Takashi Iwai wrote:
> >
> > > At Thu, 15 Nov 2007 14:28:14 -0600,
> > > Timur Tabi wrote:
> > > >
> > > > Takashi Iwai wrote:
> > > > > At Thu, 15 Nov 2007 09:00:54 -0600,
> > > > > Timur Tabi wrote:
> > > > >> Jaroslav Kysela wrote:
> > > > >>
> > > > >>> Yes, call snd_pcm_stop() function. The call must be protected with
> > > > >>> snd_pcm_stream_lock... See to i2c/other/ak4117.c for an example.
> > > > >> That code calls snd_pcm_stop() from a timer, not an ISR. Do I need the call to
> > > > >> wake_up() as well?
> > > > >
> > > > > snd_pcm_stop() can be called from ISR, too (e.g.
> > > > > snd_pcm_period_elapsed() may call snd_pcm_stop() when XRUN occurs).
> > > > > You only need to protect it via snd_pcm_stream_lock*().
> > > >
> > > > It doesn't seem to do much. Here's the function I wrote:
> > > >
> > > > static void fsl_dma_abort_stream(struct snd_pcm_substream *substream)
> > > > {
> > > > unsigned long flags;
> > > >
> > > > snd_pcm_stream_lock_irqsave(substream, flags);
> > > > if (snd_pcm_running(substream)) {
> > > > snd_pcm_stop(substream, SNDRV_PCM_STATE_DRAINING);
> > >
> > > You passed a wrong state. Usually snd_pcm_stop() passes either
> > > SNDRV_PCM_STATE_SETUP (for post-draining) or SNDRV_PCM_STATE_XRUN (for
> > > errors).
> > >
> > > > wake_up(&substream->runtime->sleep);
> > > > }
> > > > snd_pcm_stream_unlock_irqrestore(substream, flags);
> > > > }
> > >
> > > This wake_up is superfluous. Now I understand your question in the
> > > last mail...
> >
> > I'm not sure if the wake call is superfluous, if driver ends to call
> > elapsed callbacks, there is no way to wakeup process when it sleeps
> > somewhere. I think that code might be covered with a nice macro with a
> > name like 'snd_pcm_hw_stopped()' or so.
>
> But wake_up() is already in snd_pcm_post_stop(). How can this second
> call help?
Overlooked. Thanks.
Jaroslav
-----
Jaroslav Kysela <perex@xxxxxxxx>
Linux Kernel Sound Maintainer
ALSA Project
_______________________________________________
Alsa-devel mailing list
Alsa-devel@xxxxxxxxxxxxxxxx
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
