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

From: Suresh Siddha
Date: Thu Oct 22 2009 - 20:12:38 EST


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?

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