[alsa-devel] VT1708 clicks & pops

[Forest Bond]

Hi Takashi,

On Wed, Sep 21, 2011 at 04:43:15PM +0200, Takashi Iwai wrote:
> At Wed, 21 Sep 2011 10:35:10 -0400, Forest Bond wrote:
> > On Wed, Sep 21, 2011 at 10:39:44AM +0200, Takashi Iwai wrote:
> > > At Tue, 20 Sep 2011 15:05:34 -0400, Forest Bond wrote:
> > > > On Tue, Sep 20, 2011 at 09:22:23AM +0200, Takashi Iwai wrote:
> > > > > At Mon, 19 Sep 2011 19:14:13 -0400, Forest Bond wrote:
> > > > > > On Fri, Sep 16, 2011 at 04:36:01PM -0400, Forest Bond wrote:
> > > > > > > I have two boards with a VT1708:
> > > > > > > 
> > > > > > > * VIA EPIA EX15000G
> > > > > > > * VIA VB8002
> > > > > > > 
> > > > > > > I'm using VLC to play audio via PulseAudio to the analog outputs.  The VB8002
> > > > > > > sounds great, but the EX15000G has random pops and clicks in the output.  Both
> > > > > > > machines are running exactly the same configuration (they are using the same
> > > > > > > pre-built OS image).

[...]

> > > As mentioned, the usual problem is the inaccurate DMA position
> > > reporting, especially when tsched=0 helped.  It means a problem of
> > > HD-audio controller.  We have already many workarounds in the driver
> > > code, but more investigations are needed in such a case...
> > 
> > Again, I'm happy to spend the time needed to get this fixed.  If you can provide
> > hints on where to look, that would be great.  Can you point me at some git
> > commits that fixed similar issues?  I checked the git log but did not find any
> > such commits that changed patch_via.c.
> 
> Well, there are a few possible causes.  If it's something wrong in the
> codec side, it can be a PM code.  The latest driver has a mixer enum
> "Dynamic Power-Control".  Try to disable it.

This control is not enabled for the VT1708 codec because the
set_widgets_power_state function pointer is not defined for this codec.  I
assume the hardware doesn't support the underlying feature?  Or maybe it is just
not implemented yet in the driver?

Thanks,
Forest
-- 
Forest Bond
http://www.alittletooquiet.net
http://www.rapidrollout.com
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