Re: S/PDIF on AD1980 patch

[Jaroslaw Sobierski <fycio@gucio.com>]

Quoting Takashi Iwai <tiwai@suse.de>:

> > > hmm.. ICH4 has a separate SPDIF channel and it looks like we don't use
> > > this properly.  that is, SPDIF is routed via the normal slot 3/4.
> > > perhaps we should route the spdif via slot 10/11 (in GLOB_CNT bit
> > > 30:31 to 1:1), and set SPSA to the corresponding value.
> > > the definition of iec958 in ICH.conf should be rewritten, too...
> > The default configuration for ad1980 is to use slots 7/8. 3/4 is not
> > the best choice since the DACs are set to this by default. I don't
> > think ICH4 has anything to do with this, I downloaded the specs a while
> > ago only to realize that it just gives you access to the ac97 regs and
> > that's it.
> 
> no, as mentioned above, ICH4 has the configuration of SPDIF out slots
> via GLOB_CNT bits 30:31.  please check these bits.

You're absoultely right (of course). I didn't get that far in the ICH4 docs,
I thought the ac97 chapter covers it all :-).


> 
> > There's practically nothing to configure on the south bridge itself.
> > 
> > > 
> > > anyway,  can you check whether the register 0x3a is set correctly when
> > > mplayer tries to play ac3?
> > > 
> > Yes and no :-). I dumped all ac97 regs from /proc and was going to send
> > you teh list, but they did not change at all between PCM and ac3. I later
> > discovered, quite by accident, that for some reason ac3 is never routed
> > to the ac97 codec - when I choose the hwac3 option the stream always
> > goes to emu10k1 (and plays correctly over its spdif), even though I 
> > explicitly specify "hw:1". I have to try unloading the modules for emu and
> 
> > see what happens then. But this seems anyway a bug. Unless the ICH driver
> > declares no possibilty to create open ac3 stream and alsa falls back on
> > the default card? 
> 
> can you try ac3dec in alsa-tools (with -C option).
> if it works, then it's a bug of mplayer.  mplayer should access
> "spdif" or "iec958" as the pcm name.

Worked like a charm! No problem, on any of the two cards. So I guess I have
to start patching mplayer now ;-) (which I was gonna do eventually anyway,
since it doesn't handle dts streams correctly).

Thanks a lot for all your help guys! You've greatly help me enjoy my
audio experience on Linux.

Fycio. 

--------------
Fycio (J.Sobierski)
 fycio@gucio.com


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