Re: [PATCH 14/21] i386 Apm is on cpu zero only

From: Ingo Molnar
Date: Tue Nov 08 2005 - 08:26:30 EST



* Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:

> On Maw, 2005-11-08 at 04:53 -0800, Zachary Amsden wrote:
> > Can't hurt, and APM is largely obsolete because of ACPI, so I'm only
> > concerned with trimming and keeping adequate protection of the kernel
> > from APM code while maintaining correctness. I don't have a nice set of
> > old machines with enough wacky APM BIOSen to validate that unpinning the
> > CPU is ok.
>
> A large number of SMP machines, probably the majority of APM based
> ones require that APM calls occur on CPU#0. As I understand it from a
> BIOS engineer involved in debugging that problem Redmond always does
> APM from CPU #0 and may even guarantee it.

ok, then i'm all for making that more explicit - i.e. Zachary's patch is
the right one.

Ingo
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