RFC: AGP + nouveau + quirks

[Ilia Mirkin]

I was just looking at
https://bugs.freedesktop.org/show_bug.cgi?id=20341 (see last comment).
Basically he's able to to use the card with agpmode=2 but not the
auto-detected agpmode=4. I also saw that the radeon driver has a large
quirks list, and it seems silly to reproduce it in nouveau.

However the quirks in the radeon driver are a bit odd -- they are per
agp chipset/card chipset pair, rather than a blanket max speed for the
whole agp chipset. I find this surprising, but I suppose I don't know
that much about all this stuff. I was thinking for nouveau, it would
just be at the agp chipset level.

Do you guys think that it's reasonable to make the quirks list
dependent on the agp chipset only? In that case, I can refactor and
create The One True List (tm). Otherwise I'll just hack something into
nouveau inspired by the radeon list. [Also for the single list, it
might be better for the agpgart driver itself to know about the
restrictions, but that's probably more refactoring than I care for.]

Comments/suggestions/concerns appreciated.

  -ilia