Re: [PATCH] x86: introduce a new Linux defined feature flag for PATsupport

[H. Peter Anvin]

Linus Torvalds wrote:
> > *Certainly* I don't want anything like this crap:
> >
> > > -    if (cpu_has_pat)
> > > +    if (cpu_has_pat && cpu_has_pat_good)
>
> This in fact is likely the best part of it.
>
> Because that at least guarantees that we never say we have a good PAT when 
> the hardware doesn't even report it.
>
> As it is, we seem to just blindly override hardware. It may be correct for 
> all the models we override, but still..

Yah, this is not good.  We should mask out the bit, but never, ever, set 
it if it was clear to begin with (unless we have it on really, *really*, 
good authority.)

I'm embarrassed to have let that slink by.

	-hpa
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