DRM update for testing

I've got a patch at:
http://people.freebsd.org/~anholt/dri/drm-sys-20051123.diff
for testing, which merges DRM CVS into FreeBSD.  I've done basic tests
of a recent DRM CVS with WITNESS on AGP/PCI Matrox, AGP/PCI Rage 128,
AGP Radeon r100/r200/r300, AGP Savage4 (new!), SiS, and 3dfx, and this
version should be equivalent to what I tested.  I'll do another pass of
testing before I commit, but I'd also like to get some wider testing so
more panics can show up if they exist.  This particular diff has only
been compile-tested with LINT on amd64 so far.

Known issues:
- Radeon PCIGART mode hung for me.  I've heard this is caused by a
change in X.Org upstream which itself worked around a different hang, so
those of you not using xorg-server-snap wouldn't hit it hopefully.
- Savage3d untested iirc
- Savage4 PCI doesn't work (needs some love in the memory mapping
department, I think).

However, savage support has experimental and will only be on by default
with the next release of X.Org, so I feel OK with integrating it into
-current.

So, for testing: If you get instant reboots while starting/using X, that
almost always means a kernel panic.  This is new behavior in the last
year or so afaik (where a number of us have issues dumping while in X).
However, I've hooked up serial consoles and got backtraces fine, which
hopefully you can do if you hit issues, as well. 

Also, note that this brings in a new enough r300 driver for running Mesa
CVS's r300 driver, which hasn't been the case for a while.  It doesn't
bring in the via driver, which jakeb ported but which got overcome by
new linux-specific code (volunteers to work on this in DRM CVS would be
excellent!) in CVS.  Also, the i915 (i830 through i915 integrated
graphics) driver should be pretty quick for someone with a bit of newbus
knowledge to finish off, or it could be a chance someone who cared to
learn more about the FreeBSD kernel :)

-- 
Eric Anholt                                     eta_at_lclark.edu
http://people.freebsd.org/~anholt/              anholt_at_FreeBSD.org