[alsa-devel] VT1708 clicks & pops
forest at alittletooquiet.net
Wed Sep 21 19:55:53 CEST 2011
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.
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