I finally was able to install Debian on my powerpc, but the only way to get a GUI up is by disabling nouveau. I just use Linux
nouveau.modeset=0 at the yaboot prompt. However my color is all messed up like it's been washed in tie-dye.
I'm guessing I need to configure an xorg.conf to get the card to work? I have no idea what settings to put in there. Using an Nvidia GeForce 5200 FX with 64mb vram on a MAC G5.