https://bugs.freedesktop.org/show_bug.cgi?id=34618
--- Comment #15 from Alex Deucher agd5f@yahoo.com 2011-02-23 11:59:40 PST --- (In reply to comment #11)
Should I compile a kernel without MTRR an test it? I don't know how to switch of PAT, does it depend on MTRR?
If you disable pat or mtrrs it will likely be slow since you won't get write combining on the mmaped fb.