Re: [rfc] fix Kconfig, hotplug_cpu is needed for swsusp

From: Rafael J. Wysocki
Date: Thu Mar 30 2006 - 11:15:59 EST


Hi,

On Thursday 30 March 2006 10:41, Pavel Machek wrote:
> > > So if you have a single core x86, you want X86_PC, and if you have HT or SMP,
> > > you want GENERICARCH? If so, could this be done via selects or depends or at
> > > least defaults in Kconfig?
> >
> > Yes, i think only SUSPEND_SMP is affect by this.

That's correct.

> > I thought Rafael cced Pavel during that exchange, maybe i missed.

I did, but Pavel was travelling at that time (I think).

[Well, I had the feeling it would cause problems but unfortunately I couldn't
show that.]

> > How about this patch.
> >
> > Make SUSPEND_SMP depend on X86_GENERICARCH, since hotplug cpu requires !X86_PC
> > due to some race in IPI handling. See more discussion here
> >
> > http://marc.theaimsgroup.com/?l=linux-kernel&m=114303306032338&w=2
>
> I can't see useful discussion there.
>
> > Index: linux-2.6.16-git16/kernel/power/Kconfig
> > ===================================================================
> > --- linux-2.6.16-git16.orig/kernel/power/Kconfig
> > +++ linux-2.6.16-git16/kernel/power/Kconfig
> > @@ -96,5 +96,5 @@ config SWSUSP_ENCRYPT
> >
> > config SUSPEND_SMP
> > bool
> > - depends on HOTPLUG_CPU && X86 && PM
> > + depends on HOTPLUG_CPU && X86 && PM && X86_GENERICARCH
> > default y
>
>
> Heh, great, so one more magic option that is required.

BTW it's i386-centric, as X86_GENERICARCH is not defined on x86_64, for
example.

FUrther, the whole problem, as far as I can understand it, is i386-specific,
so it should be resolved in the i386 architecture config rather than anywhere
else.

Greetings,
Rafael
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