Re: [patch 0/2] suspend/resume regression fixes

From: Mark Lord
Date: Fri Sep 28 2007 - 17:18:11 EST

Thomas Gleixner wrote:
On Fri, 2007-09-28 at 16:27 -0400, Mark Lord wrote:
On a closely related note: I just now submitted a patch to fix SMP-poweroff,
by having it do disable_nonboot_cpus before doing poweroff.

Which has led me to thinking..
..are similar precautions perhaps necessary for *all* ACPI BIOS calls?

Because one never knows what the other CPUs are doing at the same time,
and what the side effects may be on the ACPI BIOS functions.

And also, I wonder if at a minimum we should be guaranteeing ACPI BIOS calls
only ever happen from CPU#0 (or the "boot" CPU)? Or do we do that already?

The ACPI calls are serialized in the kernel, AFAICT. But the fragile
situations (suspend, resume, shutdown, reboot) are probably those, where
some BIOS implementation expect that certain things are not called or
not active.

Mmm.. *do* we actually do this for reboot? I don't see it there.
And how about for kexec?

I'm probably just missing seeing it. Right?

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