[RFC/PATCH v2 0/8] Clean up write-combining MTRR addition

From: Andy Lutomirski
Date: Thu May 09 2013 - 15:46:55 EST


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 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_cleanup/rfc_v2

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

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