Comment 47 for bug 1434581

SRU Justification:

Impact: After dropping a sauce patch to make vesafb a module we accidentally dropped a change to make mtrr:3 (write-combining remap range) the default. This results in a performance degradation for graphics cards that have no drm framebuffer driver (especially on higher resolutions).

Fix: Change default for mtrr setting from none to 3 (write-combining).

Testcase: With any hardware that ends up having vesafb (VESA VGA) as framebuffer device performance is slower and the mapped address will not show up in /proc/mtrr. After changing the default /proc/mtrr should show a write-combining entry and performance should be improved.