On Thu, May 9, 2013 at 3:46 PM, Andy Lutomirski luto@amacapital.net wrote:
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 comment is wrong, as i said we need MTRR on PAT system for VRAM.
Cheers, Jerome
This series adds new functions arch_phys_wc_{add,del} that, on PAT-less x86 systems with MTRRs, add MTRRs and report errors, and that do nothing otherwise. (Other architectures, if any, with a similar mechanism could implement them.)
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/.
Changes from v1:
- Helpers renamed
- Lots of bugs fixed
The series is also at: https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/log/?h=mtrr_clea...
Andy Lutomirski (8): Add arch_phys_wc_{add,del} to manipulate WC MTRRs if needed drm (ast,cirrus,mgag200,nouveau,savage,vmwgfx): Remove drm_mtrr_{add,del} drm: Update drm_addmap and drm_mmap to use PAT WC instead of MTRRs drm,agpgart: Use pgprot_writecombine for AGP maps and make the MTRR optional i915: Use arch_phys_wc_{add,del} radeon: Switch to arch_phys_wc_add and add a missing ..._del uvesafb: Clean up MTRR code drm: Remove mtrr_add and mtrr_del fallback hack for non-MTRR systems
Documentation/fb/uvesafb.txt | 16 +++----- arch/x86/include/asm/io.h | 7 ++++ arch/x86/include/asm/mtrr.h | 5 ++- arch/x86/kernel/cpu/mtrr/main.c | 48 +++++++++++++++++++++++ drivers/char/agp/frontend.c | 8 ++-- drivers/gpu/drm/ast/ast_ttm.c | 13 ++----- drivers/gpu/drm/cirrus/cirrus_ttm.c | 15 ++------ drivers/gpu/drm/drm_bufs.c | 17 +++++---- drivers/gpu/drm/drm_pci.c | 8 ++-- drivers/gpu/drm/drm_stub.c | 10 +---- drivers/gpu/drm/drm_vm.c | 22 +++++------ drivers/gpu/drm/i915/i915_dma.c | 44 +++------------------ 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 | 43 ++++++++------------- 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 | 34 +---------------- include/drm/drm_os_linux.h | 16 -------- include/linux/io.h | 25 ++++++++++++ include/video/uvesafb.h | 1 + 23 files changed, 181 insertions(+), 268 deletions(-)
-- 1.8.1.4