[alsa-devel] spdif/iec958 outputs at VT1708S not recognized

David Douglas one51s at yahoo.com
Wed Apr 29 17:19:06 CEST 2009

Peter Niemayer <niemayer <at> isg.de> writes:
> I recently installed an Asus M4N78 mainboard, that uses a
> nVidia GeForce 8300 chipset and a VT1708S soundchip.
> I had to short circuit the pin definition
> in vt1708S_parse_auto_config() to get the digital outputs
> to work:
>          spec->multiout.max_channels = spec->multiout.num_dacs * 2;
> -       if (spec->autocfg.dig_out_pin)
> +       // test fails for Asus M4N78 if (spec->autocfg.dig_out_pin)
>                  spec->multiout.dig_out_nid = VT1708S_DIGOUT_NID;
>          spec->extra_dig_out_nid = 0x15;

Hi Peter,

I'm a relative Linux newbie trying to get away from Windows.  But longtime
computer geek.  I have an issue with my Asus M4A78 (same as yours but ATI
graphics), that the LFE channel works in speaker-test but has no output from
applications (even when they should output 5.1, like a DVD in VLC).

I believe that some layer, maybe even the hw, is remixing to 5 (minus the .1)
without being asked, as even CD sound plays over all five speakers.  And there
is no gui configuration program I can find to specify such a remixing (which I
am sure the soundcard is capable of).

Currently I am trying an upgrade (via script from ubuntu forums) to the latest
Alsa, from .18 to .19.  If that doesn't resolve (and I don't expect it to): I am
curious if you got 5.1 working properly with your soundcard.  Also the SPDIF
would be an option for me, can I ask the location of that code you mentioned? 
(If it's a config file and you wouldn't mind posting yours, would be fantastic).

I have been under the impression that the 1708S is not explicitly supported by
Alsa, because it's not yet listed in the Alsa-project homepage list  :-/

Many thanks,

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