AMD64 K8 Family C1E dead apic timer fixup

[Ariff Abdullah]

On Mon, 23 Apr 2007 14:46:53 -0400
John Baldwin <jhb at freebsd.org> wrote:
> On Friday 20 April 2007 07:54:44 am Ariff Abdullah wrote:
> > Will anybody object if I (or somebody else) commit this patch?
> > 
> >    http://people.freebsd.org/~ariff/test/k8_c1e.diff
> > 
> > This should "fix" dead apic timer issues on latest AMD64 (Turion64
> > X2 mostly, or later revision) where C1 Enhanced (C1E) mode
> > enabled.
> > 
> > Without this, the only way to make the timer work is to disable
> > APIC or even worst, to avoid executing HLT instruction
> > (machdep.cpu_idle_hlt=0), smp or non-smp. It affect both i386 and
> > amd64.
> > 
> > See PR: i386/104678 for details.
> 
> Does this fix all of the Turion lapic timer hangs?

Yes, and hopefully to the later revisions (if any) as well.

> Some small tweaks to the  comment would be:
> 
> - s/present/presence/
> - s/render/renders/
> - s/apic timer/local APIC timer/
> - s/dead, and/dead, so/
> - s/reading Interrupt/reading the Interrupt/
> - s/unset/clearing/
> 

Thanks.

> Also, is it ok to always mask off the upper 31 bits of the MSR
> instead of  preserving their current state?
> 
It should work either way, since the upper bits are read only.



--
Ariff Abdullah
FreeBSD

... Recording in stereo is obviously too advanced
    and confusing for us idiot ***** users :P ........
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