* Re: [patch 0/4] gpu/drm, x86, PAT: Add PAT support for io_mapping_* interface
[not found] <20090225013510.010493000@intel.com>
@ 2009-02-25 12:08 ` Ingo Molnar
2009-02-25 14:06 ` Pallipadi, Venkatesh
0 siblings, 1 reply; 3+ messages in thread
From: Ingo Molnar @ 2009-02-25 12:08 UTC (permalink / raw)
To: Venkatesh Pallipadi, Linus Torvalds
Cc: Dave Airlie, Jesse Barnes, Eric Anholt, Thomas Gleixner,
H Peter Anvin, Keith Packard, linux-kernel
* 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.
Linus, do you have any preference?
Ingo
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: [patch 0/4] gpu/drm, x86, PAT: Add PAT support for io_mapping_* interface
2009-02-25 12:08 ` [patch 0/4] gpu/drm, x86, PAT: Add PAT support for io_mapping_* interface Ingo Molnar
@ 2009-02-25 14:06 ` Pallipadi, Venkatesh
2009-02-25 15:41 ` Ingo Molnar
0 siblings, 1 reply; 3+ messages in thread
From: Pallipadi, Venkatesh @ 2009-02-25 14:06 UTC (permalink / raw)
To: Ingo Molnar, Linus Torvalds
Cc: Dave Airlie, Jesse Barnes, Eric Anholt, Thomas Gleixner,
H Peter Anvin, Keith Packard, linux-kernel
>-----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
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [patch 0/4] gpu/drm, x86, PAT: Add PAT support for io_mapping_* interface
2009-02-25 14:06 ` Pallipadi, Venkatesh
@ 2009-02-25 15:41 ` Ingo Molnar
0 siblings, 0 replies; 3+ messages in thread
From: Ingo Molnar @ 2009-02-25 15:41 UTC (permalink / raw)
To: Pallipadi, Venkatesh
Cc: Linus Torvalds, Dave Airlie, Jesse Barnes, Eric Anholt,
Thomas Gleixner, H Peter Anvin, Keith Packard, linux-kernel
* Pallipadi, Venkatesh <venkatesh.pallipadi@intel.com> wrote:
> >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.
ok, i've delayed #3/#4 to .30 and kept #1/#2 in tip:x86/urgent.
No complications so far with any of them.
Ingo
^ permalink raw reply [flat|nested] 3+ messages in thread
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2009-02-25 12:08 ` [patch 0/4] gpu/drm, x86, PAT: Add PAT support for io_mapping_* interface Ingo Molnar
2009-02-25 14:06 ` Pallipadi, Venkatesh
2009-02-25 15:41 ` Ingo Molnar
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