[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).
> > > > The crackling with PCM volume set to 0 persists with tsched=0.

[...]

> > > Hrm, which PA version are you using?  I remember vaguely a buggy PA
> > > SIMD operations in some old PA versions.
> > 
> > 1:0.9.22+stable-queue-24-g67d18-0ubuntu3 from Ubuntu Lucid.
> > 
> > > Also, when you mute the mixer (nor the PA's mixer), e.g. via
> > > "alsamixer -c0", the noise goes away, right?
> > 
> > I do not use the PA mixer.  The noise is present with ALSA's PCM control set to
> > zero (-51dB).  If I move the PCM control up one tick (to -50.8dB) the noise goes
> > away.
> 
> OK, then it's an issue in the sound driver.
> Could you give alsa-info.sh outputs both mute-with-noise and without
> noise for comparison?

I guess we can ignore this one for now.  I do not have this problem using a
recent alsa-driver snapshot.  The PCM control does not go below -40.25dB with
this version.  It's possible the new driver simply doesn't allow the control to
be set to a problematic value.

I will note, however, that the master control with the snapshot has a minimum
value of 0dB and a maximum of 6.75dB, and that the audio is barely audible at
0dB.  I have to crank the master control all the way up to get the same volume
as the old driver set to 0dB.  Maybe I can come up with a fix for this.

Thanks,
Forest
-- 
Forest Bond
http://www.alittletooquiet.net
http://www.rapidrollout.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
Url : http://mailman.alsa-project.org/pipermail/alsa-devel/attachments/20110921/627e20ba/attachment.sig