[Alsa-user] via82xx: s/pdif works (kind of) but not AC3

[Gadi C. <dr...@wa...>]

Hi,

VIA 8235 / Realtek ALC650F
Its integrated inside my laptop, so no jumper settings to play with.

I can get the S/PDIF "Digital out" working, although I can only get 2
channels working at a time.  Depending on the position of the IEC958
dial on my mixer, I either get some strange results:

$ amixer set 'IEC958 Playback AC97-SPSA' 0
$ mplayer -ao alsa -channels 6 chan-id.wav

With '0': front left and front right to correct speakers, nothing else

With '1': 'center' goes to FL, weird mix of rear l+r goes to FR
(incidentally, using my laptop's internal speakers, I get the same weird
mix after the center channel, but then properly on both RL and RR
afterwards -- maybe just the file i'm using).

With '2': rear left and right goes to front left and right, nothing else

With '3' and '4': nothing

This behaviour is kind of explained in the EPIA howto here:
http://www3.sympatico.ca/howlettfamily/epia/epia_howto/x310.html - so it
looks like I can always only get two channels unless I use anologue
output??

Anyways, my bigger problem is that I can't get the AC3 passthrough
working.  As said, digital out works fine, but as soon as I add -ac
hwac3 to mplayer (or with xine, whatever), my receiver loses the signal.
As soon as I stop playing, the signal comes back.

I was previously using things with an sblive with the same settings and
things worked fine, so the receiver is definitely not the problem.

Also, while I'm here...  when decoding AC3 to 6 channels via software to
the laptops internal speakers (should I really have to do this?  or
should the IEC958 handle this?) the center speaker output doesnt go to
the subwoofer aswell... is this something i'd fix somehow with my
.asoundrc?

Many many thanks to anyone who helps me with this!

Gadi