Re: [3/3] 2.6.23-rc2: known regressions v2

[Sam Ravnborg <sam@ravnborg.org>]

On Mon, Aug 13, 2007 at 10:59:41PM +0200, Rafael J. Wysocki wrote:
> On Monday, 13 August 2007 20:35, Sam Ravnborg wrote:
> > On Mon, Aug 13, 2007 at 03:21:54PM +0200, Michal Piotrowski wrote:
> > > > >
> > > > > The patch changes the warning to a different warning, it's now
> > > > > kernel/power/Kconfig:79:warning: 'select' used by config symbol 'PM_SLEEP_SMP' refers to undefined symbol 'HOTPLUG_CPU'
> > 
> > So we have something like this for ppc:
> > 
> > config PM_SLEEP_SMP
> > 	bool "bla bla"
> 
> Plus a couple of "depends on ..." here, which cannot be true.
> 
> > 	select HOTPLUG_CPU
> > 
> > As it is not in my -linus tree it has been added by the referanced patch
> > in the text I zapped.
> > 
> > 
> > The warning is generated _independently_ of the actual configuration.
> > All it says is that the symbol PM_SLEEP_SMP has a seelct statement
> > for an unknown symbol - unknown for this architecture at least.
> > 
> > Grepping will reveal that HOTPLUG_CPU is not present for ppc and
> > the easiet fix here seems to just add it like in the following:
> > 
> > diff --git a/arch/ppc/Kconfig b/arch/ppc/Kconfig
> > index 6bdeeb7..e7bcd57 100644
> > --- a/arch/ppc/Kconfig
> > +++ b/arch/ppc/Kconfig
> > @@ -65,6 +65,10 @@ config GENERIC_BUG
> >         default y
> >         depends on BUG
> >  
> > +config HOTPLUG_CPU
> > +       bool
> > +       default n
> > +
> >  source "init/Kconfig"
> >  
> >  menu "Processor"
> > 
> > [cut'n'paste so whitespace damaged...]
> > This will silence the warning...
> > 
> > 
> > Now as PM_SLEEP_SMP requires HOTPLUG_CPU there most be done
> > something else to prevent this config symbol to be selected
> > otherwise we would end up with a kernel that has HOTPLUG_CPU
> > defined even it is not supported.
> 
> Well, the issue at hand is that PM_SLEEP_SMP will never be set on this arch
> and the warning is printed nevertheless.

Yep - because the warnign is correct.
The symbol PM_NEED_SMP refer to an undefined symbol
no matter the case that PM_NEED_SMP can be set or not.

So either provide the symbol or drop the select. It is as simple as that.

	Sam