Re: regression in 2.6.23-rc8 - power off failed

From: Rafael J. Wysocki
Date: Sat Sep 29 2007 - 16:53:37 EST

On Saturday, 29 September 2007 22:47, Bill Davidsen wrote:
> Alexey Starikovskiy wrote:
> > -static void
> > -acpi_power_off (void)
> > -{
> > - printk("%s called\n",__FUNCTION__);
> > - /* Some SMP machines only can poweroff in boot CPU */
> > - set_cpus_allowed(current, cpumask_of_cpu(0));
> > ACPI in kernel 2.6.12 did disable non-boot cpus too in powe_off.
> > Later only comment was left for some reason...
> >
> Am I midreading that code, or does it really assume that the boot cpu is
> always zero? Or just that zero will be able to do the power off?
> In any case I have had an SMP machine which did not have a CPU zero, and
> it was discussed here, I believe. Wonder what happens if you set
> affinity to a CPU you don't have...

Good question, but it also caused other problems to appear, IIRC.

IMHO, it's better to call disable_nonboot_cpus() in an appropriate place

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