Re: [PATCH] x86: mtrr cleanup for converting continuous to discrete - auto detect v2

From: Yinghai Lu
Date: Thu May 01 2008 - 17:31:38 EST


On Thu, May 1, 2008 at 2:26 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> Yinghai Lu wrote:
>
> >
> > >
> > > >
> > > >
> > > Yes, 16 GB systems are already mainstream; 32 GB is common, so I don't
> see
> > > any reason to stop at 2 GB. Instead, it should loop up to the physical
> > > address size.
> > >
> >
> > but our objective is that has 0xd0000000-0xe0000000 (WC) not to be
> > overlapping with other MTRR entries (UC)..
> >
> >
>
> So, pray tell, how comes this algorithm can come up with a non-solution to
> the problem presented to it?
>
> Overall, I'm feeling there is something really completely wrong if this
> needs manual tunables of any sort.

the problem is BIOS set MTRR like BIG WB - SOME SAMLL UC to spare mtrr regs.

but later X server driver want to set some range to WC. that already
is fallen in UC...

YH
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