Re: [patch 0/4] x86: PAT followup - Incremental changes and bug fixes

Andreas Herrmann3
2008-01-17T23:10:34Z

On Thu, Jan 17, 2008 at 11:35:51PM +0100, Ingo Molnar wrote:
>
> * Andreas Herrmann3 <andreas.herrmann3@amd.com> wrote:
>
> > > I'll check this asap
> >
> > So, now that I've avoided this tiny NULL-pointer-dereference, the
> > system boots fine as well with your (slightly modified) patch. See
> > dmesg attached.
>
> for now i applied your ioremap_uncached() patch and removed my patch.
>
> my patch might work if the MTRR marks that area UC. Does it on your
> system?

The region (c0403000-c04031ff) is not characterized by an MTRR.
The MTRRdefType specifies it and it is

MTRRdefType = 0x0000000000000c00
MemType=0
MtrrDefTypeFixEn=0x1
MtrrDefTypeEn=0x1

=> 0==UC

So, that's why it worked.

Andreas