A fair number of drivers (mostly graphics) add write-combining MTRRs. Most ignore errors and most add the MTRR even on PAT systems which don't need to use MTRRs.
This series adds new functions mtrr_{add,del}_wc_if_needed and drm_mtrr_{add,del}_wc that report errors and do nothing if PAT is enabled.
I've only tested the radeon driver, since I don't have test hardware easily available for the other drivers.
Benefits include: - Simpler code - No more complaints about MTRR conflict warnings on PAT systems - Eventual unexporting of the MTRR API?
This series eliminates about half of the mtrr_add calls in drivers/.
The series is also at: https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/log/?h=mtrr_clea...
Andy Lutomirski (7): x86: Add mtrr_{add,del}_wc_if_needed drm (ast,cirrus,mgag200,nouveau,savage,vmwgfx): Rework drm_mtrr_{add,del} drm: Update drm_addmap and drm_mmap to use PAT WC instead of MTRRs drm: Use drm_mtrr_add_wc for the AGP aperture i915: Use drm_mtrr_{add,del}_wc radeon: Switch to drm_mtrr_add_wc and add a missing drm_mtrr_del_wc uvesafb: Clean up MTRR code
Documentation/fb/uvesafb.txt | 16 +++----- arch/x86/include/asm/mtrr.h | 21 ++++++++++ arch/x86/kernel/cpu/mtrr/main.c | 53 +++++++++++++++++++++++++ drivers/gpu/drm/ast/ast_ttm.c | 14 ++----- drivers/gpu/drm/cirrus/cirrus_ttm.c | 15 ++------ drivers/gpu/drm/drm_bufs.c | 11 ++---- drivers/gpu/drm/drm_pci.c | 8 ++-- drivers/gpu/drm/drm_stub.c | 10 +---- drivers/gpu/drm/drm_vm.c | 13 ++++--- drivers/gpu/drm/i915/i915_dma.c | 43 +++------------------ drivers/gpu/drm/mgag200/mgag200_ttm.c | 14 ++----- drivers/gpu/drm/nouveau/nouveau_ttm.c | 13 ++----- drivers/gpu/drm/radeon/radeon_object.c | 5 ++- drivers/gpu/drm/savage/savage_bci.c | 42 ++++++++------------ drivers/gpu/drm/savage/savage_drv.h | 5 +-- drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 10 ++--- drivers/video/uvesafb.c | 70 +++++++++------------------------- include/drm/drmP.h | 23 +++++------ include/video/uvesafb.h | 1 + 19 files changed, 169 insertions(+), 218 deletions(-)