[Nouveau] RFC: drop glamor from nouveau ddx

[Ilia Mirkin]

Ben,

Looks like the reality is that glamor is just not hooked up properly
in the nouveau DDX. Mainly it's missing DRI2, which in turn means no
core GL contexts, and probably lots of other issues. While this could
probably be fixed somehow, I doubt there's any advantage to using the
nouveau DDX over something like modesetting nowadays.

How would you feel about dropping glamor support from the nouveau ddx
and failing to load for GPUs that don't have EXA support (unless
AccelMode = none is forced for them). That way it'll fall back to
loading modesetting which should be properly set up for DRI2 and so
on.

Cheers,

  -ilia