Asus P4S8X - SiS 7012 audio with C-Media 9739 codec

[David Monniaux <David.Monniaux@ens.fr>]

Hi,

I have a SiS 648-based motherboard (Asus P4S8X) with a SiS 7012 AC'97 
audio coupled with a C-Media 9739 codec (id 0x434D4961).

For some reason, mixer settings under Linux work in a binary fashion: 
either mute, or full volume, but no gradation.

I've fixed ac97_codec.c so that it detects the codec, but then I'm 
stuck. I got the 9739 technical documentation from C-Media's site, but 
it does not help much - it seems that the values put in the registers 
are all right.

I suspect some bypass mechanism or some bit that turns analog mixing 
off, but I don't see anything in the documentation about it.

Would somebody with the same motherboard care to do some experiments? 
Playing a sample with xmms, one can set volume to "mute", any other 
value gives a constant volume.

It's also impossible to record anything - the recording is blank.

Regards,
D. Monniaux