hm, the page you linked says
and audio is supported via the i810_audio, or snd-hda-intel (for MCP55 and later chipsets) drivers
I need the old drivers because i810_audio cannot use the optical out connector - only the old nforce drivers can use the connector. The page that I linked in my first post says this, too:
The open source alsa driver (intel8x0) is not capable of hardware mixing or dolby digital encoding. I only manage to get sound from one application at the time and only in stereo and analog output. In my experience nvidias closed source oss drivers work (almost) perfectly.
I just wonder why the old driver package workes perfectly under 2.6.18 and not under 2.6.21.
But i'll try with the alsa drivers again...