Kenneth Culver wrote:
> Yeah, that's what I saw on linux-kernel...
> 
> Ken

We need to use the PAT cpu_features feature.  This gives us 8 page attribute
modes instead of simple no-cache / writethrough flags.  We can (and must)
control more carefully the speculative hardware prefetch, for example.

I've been thinking about this with the pmap revamp that I'm working on.
It may solve the athlon problems too.

> On Thu, 31 Jan 2002, Cameron, Frank wrote:
> 
> > From what was posted on the linux-kernel list the problem is the OS
> > doing the wrong thing not the hardware.  I originally asked the
> > question (albeit not worded as clearly as I should have) because if
> > Microsoft and Linux programmers made the same mistake, might
> > FreeBSD have also.
> >
> > > -----Original Message-----
> > > From: Kenneth Culver [mailto:[EMAIL PROTECTED]]
> > > Sent: Thursday, January 31, 2002 10:42 AM
> > > To: Terry Lambert
> > > Cc: David Malone; Cameron, Frank; '[EMAIL PROTECTED]';
> > > '[EMAIL PROTECTED]'
> > > Subject: Re: AMD AGP Bug
> > >
> > >
> > > > There's actually a seperate TLB bug, but FreeBSD doesn't
> > > > trigger that one, either (Linux can tickle it, when there
> > > > are certain specific circumstances met).
> > > >
> > > Well, I think I know what you're talking about, linux
> > > allocates agpgart
> > > memory without setting a "non-cacheable" bit, and then the
> > > agp card writes
> > > to that memory, but the cpu cached it already, which makes
> > > the cache wrong
> > > or something like that, and causes the crashes/hangs. I know this is a
> > > greatly simplified version of the real problem, but I think this is a
> > > linux bug not necesarily an amd bug.
> > >
> > > Ken
> > >
> >
> >
> 
> 
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Cheers,
-Peter
--
Peter Wemm - [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED]
"All of this is for nothing if we don't go to the stars" - JMS/B5


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