[alsa-devel] [PATCH] pcm: Don't store the state for SND_PCM_STATE_SUSPENDED

[Shengjiu Wang]

Hi

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai at suse.de]
> Sent: Friday, May 20, 2016 10:32 PM
> To: Shengjiu Wang
> Cc: perex at perex.cz; alsa-devel at alsa-project.org
> Subject: Re: [PATCH] pcm: Don't store the state for
> SND_PCM_STATE_SUSPENDED
> 
> On Fri, 20 May 2016 12:46:37 +0200,
> Takashi Iwai wrote:
> >
> > On Fri, 20 May 2016 11:41:25 +0200,
> > Shengjiu Wang wrote:
> > >
> > > Hi Takashi
> > >
> > >    I tested your patch, after suspend and resume, the playback is
> stopped.
> > > It is caused by the DMA. DMA is not started after resume.
> > >
> > > With your patch, DMA is not terminated but then is re-started. The
> driver don't
> > > support this behavior.
> >
> > If so, it's simply a driver bug.  Blame the kernel driver instead.
> 
> Which driver did you see the problem?  We should fix it.

But my thought is when suspended, the dmaengine_pause() is called, then
dmaengine_resume() should be called in resume(). If there is no resume()
Just call the prepare() and start(), it seems not reasonable. What do
you think?

Best regards
Wang shengjiu
> 
> 
> thanks,
> 
> Takashi