Re: S/PDIF on AD1980 patch

[Jaroslaw Sobierski <fycio@gucio.com>]

Quoting Takashi Iwai <tiwai@suse.de>:

> At Mon, 17 Feb 2003 08:01:27 -0800,
> Jaroslaw Sobierski wrote:
> > 
> > 
> > Another question though. I still cannot get the AC3 pass-through to work.
> > I assume the spdif source must be set to AC-Link (which is hw-reset default
> 
> > anyway), and I figure all other stuff should be set by alsa (like
> Category
> > Code, etc.). I have no problem with AC3 on emu10k1, so I guess mplayer is
> > requesting correct stream params from alsa. Yet on AC97 I can't get it to
> 
> > work (amp keeps indicating a PCM stream). Any suggestions what to look
> for?
> 
> 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. 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? 

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


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