arch_phys_wc_add
adev->gmc.vram_mtrr = arch_phys_wc_add(adev->gmc.aper_base,
arch_phys_wc_add(map->offset, map->size);
ggtt->mtrr = arch_phys_wc_add(ggtt->gmadr.start, ggtt->mappable_end);
rdev->mc.vram_mtrr = arch_phys_wc_add(rdev->mc.aper_base,