[alsa-devel] Problems with ALC882

Takashi Iwai tiwai at suse.de
Fri Jan 18 17:20:56 CET 2008

At Fri, 18 Jan 2008 17:10:06 +0100,
Christophe Osuna wrote:
> 2008/1/16, Takashi Iwai <tiwai at suse.de>:
> > At Wed, 16 Jan 2008 18:20:20 +0100,
> > Christophe Osuna wrote:
> > >
> > > I am having a bad time trying to get an ALC882 [1] to work. I hope
> > > that you can help me. Currently I am using alsa-driver-1.0.14 but it
> > > would probably be the same with 1.0.15 since there has been no change
> > > in /pci/hda/.
> >
> > There have been tons of changes for HD-audio between these versions :)
> > You should have looked at alsa-driver*/alsa-kernel/pci/hda.
> >
> > Anyway, now it's much better to try the latest ALSA HG version than
> > 1.0.15.  1.0.15 is so old.  If you are not familiar with HG, try the
> > daily snapshot tarball below:
> >
> >         ftp://ftp.suse.com/pub/projects/alsa/snapshot/
> >
> I have tried alsa-driver-hg20080117; it shows two additional mixer
> options (Mic Boost and Front Mic Boost) but in the end it's the same:
> I am unable to access the 3rd ADC.

Looks like your board disables the third ADC.  The driver probes it
and the codec returns it's no audio-input widget.  Check codec#* proc

> The ALC882 datasheet states that "3 stereo ADCs support 16/20-bit PCM
> format, two for microphone array, one for legacy mixer recording".
> This is the only place that suggests there could be a difference, but
> I do not understand this sentence as "only 2 ADC can be used at a
> time" (English is not my native language). The block diagram in the
> following page does not suggest such a limit either.

The reality bites sometimes :)

> Besides that I have read in the same datasheet that "rates in
> sub-multiples (1/n) of 48kHz are interleaving n frames containing no
> sample blocks" and so we can have 8 kHz by setting one sample block
> every six frames. Still, I can't set the device to 8 kHz.

How did you test it?  The driver itself supports 8kHz, as long as the
codec chip really returns the capability.

Using two ALC882 codecs on the same HD-audio bus isn't supported right
now.  The second codec would conflict.  Dual audio codecs are not
impossible but it makes things complicated. 


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