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

[Andreas Herrmann3]

On Thu, Jan 17, 2008 at 11:35:51PM +0100, Ingo Molnar wrote:
> 
> * Andreas Herrmann3 <andreas.herrmann3@xxxxxxx> 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



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