Comment 2 for bug 949288

I've been playing a bit more with this. I now think it is agpgart rather than uninorth_agp that influences whether KMS reverts to PCI mode or not. Well that is what it seems to be under 10.04. Agpgart is built into 12.04 already so I guess the nouveau people have been using AGP mode all along? It is hard to tell what affects what as the boot order can be quite random it seems and small things can have a 'butterfly' effect.

The parameter video=ofonly works well under 10.04 to disable the radeonfb framebuffer. This gives a very nice splash screen . However, I cannot replicate this under 12.04. The colours are all messed up (particularly on shutdown) and nothing I seem to do can correct this. As described in post 1, video=offb:off video=radeonfb:off gives the best splash results on boot, but has no effect on shutdown.