Re: [RFC Patch] use MTRR for write combining if PAT is notavailable

[Eric Anholt]

On Thu, 2009-10-22 at 17:11 -0700, Suresh Siddha wrote:
> On Thu, 2009-10-22 at 16:10 -0700, Jesse Barnes wrote:
> > On Thu, 22 Oct 2009 14:47:30 -0700
> > Suresh Siddha <suresh.b.siddha@xxxxxxxxx> wrote:
> > 
> > > On Thu, 2009-10-22 at 08:34 -0700, Eric Anholt wrote:
> > > > Can we just not create the _wc sysfs entry if we don't have PAT?  I
> > > > don't think there's userland relying on its presence as opposed to
> > > > the non-_wc entry.
> > > 
> > > Yes indeed. Jesse do you see an issue with this? This is simple and
> > > clean. Thanks Eric.
> > 
> > Yeah, I think that will be fine.  In fact, older versions of
> > libpciaccess will behave better if we do it that way (iirc it only
> > allocates an MTRR if the resource_wc file doesn't exist or fails to get
> > mapped).
> 
> Eric, care to send the patch?

I don't have a patch, I was just suggesting a way to handle the
submitter's problem that won't involve complicated changes that nobody
else will be testing since everyone *should* have a graphics driver for
their graphics hardware.

-- 
Eric Anholt
eric@xxxxxxxxxx                         eric.anholt@xxxxxxxxx

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