Re: [PATCH] cpuidle: fix ARCH_NEEDS_CPU_IDLE_COUPLED dependency warning

[Colin Cross <ccross@android.com>]

On Fri, Jun 7, 2013 at 9:21 AM, Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Friday 07 June 2013, Santosh Shilimkar wrote:
> > > diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
> > > index f49cd51..831e89e 100644
> > > --- a/arch/arm/mach-omap2/Kconfig
> > > +++ b/arch/arm/mach-omap2/Kconfig
> > > @@ -83,7 +83,7 @@ config ARCH_OMAP4
> > >       depends on ARCH_OMAP2PLUS
> > >       depends on ARCH_MULTI_V7
> > >       select ARCH_HAS_OPP
> > > -     select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP
> > > +     select ARCH_NEEDS_CPU_IDLE_COUPLED if (SMP && CPU_IDLE)
> >
> > I remember Colin mentioning about above dependency is taken care
> > already in design [1]
>
> It's a matter of how it gets represented in Kconfig. Right now
> the ARCH_NEEDS_CPU_IDLE_COUPLED symbol has a dependency on CPU_IDLE,
> so we cannot select it if CPU_IDLE is not set (or get a build time
> warning).
>
> I originally suggested removing the dependency, but Daniel preferred
> to leave it there as an explicit dependency so it is required to
> do this change instead.

ARCH_NEEDS_CPU_IDLE_COUPLED should never have been moved inside "if
CPU_IDLE".  It was designed to be outside the CPU_IDLE dependency so
archs could select it without having to know about its dependencies.
Just move it back outside if CPU_IDLE in drivers/cpuidle/Kconfig and
you won't have to mess with every arch that uses it.  If CPU_IDLE=n
none if it will get compiled, so there is no need for the extra
dependency.