Re: [stable] [patch 09/12] Fix SMP poweroff hangs

On Tue, Oct 09, 2007 at 04:27:06PM -0700, Linus Torvalds wrote:

On Wed, 10 Oct 2007, Thomas Gleixner wrote:

quoted

Wrapping it into a #ifdef CONFIG_X86 would be sufficient.

Well, the ppc oops seems to be a ppc bug regardless.

If CPU_HOTPLUG isn't defined, the thing does nothing. And if it is 
defined, I don't see why/how ppc can validly oops. So I think the first 
thing to do is to try to figure out why it oopses, not to disable it for 
ppc.

The machine Paul tried on most likely has MPIC interrupt controller, and
the oops was when the pseries_cpu_disable tried calling XICS code instead.
It's not surprising that it failed, I don't think IBM has (traditionally)
cared about cpu hotplug on those machines.

So the PPC-side fix is to not enable cpu hotplug on mpic-based
systems. I'll follow up with a patch, but I have no way to test it since
I only have one POWER5 machine, no other IBM hardware. I'd appreciate
it if someone with hardware could verify it.


-Olof