Re: [Openvortex-dev] Alsa-XMMS buffer time weirdness / Quad codec

[Ryan Underwood]

Hi Manuel,

On Mon, Jul 07, 2003 at 11:34:23AM -0400, Manuel Jander wrote:
> > > either the SDAC output comming from the "Surround" volume control or the
> > > Main mixer output, i can get both outputs of my MX300 (SDAC_OUT and
> > > LINE_OUT) with a stereo stream only if i play through the SDAC instead
> > > the PCM DAC.
> > 
> > Hmm, having trouble picturing what's going on there.  Perhaps a little
> > ascii diagram?
> 
> Take a look at the datasheet...

Ok, I see it now on p.23, was looking at p.7 before. ;)

According to the description of 0x6e though, it would seem that both
inputs of that mux would be enabled if D2 is set (it claims that both
the SDAC output and the stereo->4ch output would be mixed together on
the rear output).  Which would be very strange.

> > > I was unable to alter the MUX in such a manner that the SDAC_OUT get its
> > > signal from the main mixer output, whoich would be preferable.
> > > 
> > > Did you have any success chaning that MUX by (supposedly) setting the
> > > bit D2 of register 0x6E ?
> > 
> > When the register 0x6e is set, the sound that goes to the primary output
> > on the codec is simply duplicated to the secondary output as well,
> > internally to the codec.
> > 
> > According to the datasheet, any sound that would go to the surround
> > output is also mixed with the (duplicated) stereo stream if that D2 is
> > set.  Which makes it preferable to _not_ set it if one is useing 4
> > discrete channels at once.  If you did, you would hear both the discrete
> > surround output as well as the duplicated front outputs both at once
> > through the rear speakers, which probably is not desirable. :)
> > 
> > Did that answer the question?
> 
> I already know that. But the D2 bit doesnt have any effect on my MX300.
> I would like too know if you had any success doing this (setting bit D2)
> ??

Ah, well, it definitely works on my SQ2500.  I have front speakers
hooked up to play movies in the other room, and my headphones are
plugged in to the rear output, the same sound comes out of both if the
4-channel stereo is enabled, and nothing comes out of rear output if
4-channel stereo is disabled.

I have two SQ2500's, a generic Vortex2, and a MX300.  I looked at all of
them and they have the same STAC9708T albeit with different date code.
but that should not make a difference.  I am not sure why setting that
bit on your MX300 would make no difference.  Are you setting it directly
or useing the WriteCodec function to do it?

Perhaps I can try the driver with all my cards and see the differences
in each.

-- 
Ryan Underwood, <nemesis at icequake.net>, icq=10317253