Messages in this thread | | | From | "Pallipadi, Venkatesh" <> | Date | Wed, 25 Feb 2009 06:06:59 -0800 | Subject | RE: [patch 0/4] gpu/drm, x86, PAT: Add PAT support for io_mapping_* interface |
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>-----Original Message----- >From: Ingo Molnar [mailto:mingo@elte.hu] >Sent: Wednesday, February 25, 2009 4:09 AM >To: Pallipadi, Venkatesh; Linus Torvalds >Cc: Dave Airlie; Jesse Barnes; Eric Anholt; Thomas Gleixner; H >Peter Anvin; Keith Packard; linux-kernel@vger.kernel.org >Subject: Re: [patch 0/4] gpu/drm, x86, PAT: Add PAT support >for io_mapping_* interface > > >* Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> wrote: > >> io_mapping_create_wc(), io_mapping_free() and associated >map/unmap routines >> are relatively new set of APIs for drivers, that change memory type. >> >> Currently, these interfaces hardcode WC type on x86 and does >not go through >> "PAT enforcement". This patchset adds PAT support for this interface. >> >> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> >> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> > >hm, the patches look sane and clean and mostly factor out >existing code and checks and apply them to the io_mapping_*() >interfaces - so it's something worth having for .29. > >But it's all rather awfully late in the cycle and ioremap type >of bugs typically have 1-2 rc's of latency to be fully >discovered. > >They will probably fix a few regressions and are easy to revert, >plus they affect the one driver whose authors wrote these >facilities: > > drivers/gpu/drm/i915/i915_dma.c > drivers/gpu/drm/i915/i915_gem.c > >so maybe we should try it as it's all a clear step forward. I'll >give them a spin in tip:x86/urgent. Dunno. >
Actual PAT support (patch 3 and 4) can probably wait until .30. As there is only one user of this interface. Patch 1 and 2 are more in bugfix category and probably considered for .29.
Thanks, Venki
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