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SubjectRe: [PATCH 2/4]: CPUIDLE: Introduce architecture independent cpuidle_pm_idle in drivers/cpuidle/cpuidle.c
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On Fri, 2009-08-28 at 08:48 +0200, Peter Zijlstra wrote:
>
> > void cpuidle_install_idle_handler(void)
> > {
> > .........
> > .........
> > cpuidle_pm_idle = cpuidle_idle_call;
> > }
>
> All I'm seeing here is a frigging mess.
>
> How on earths can something called: cpuidle_install_idle_handler() have
> a void argument, _WHAT_ handler is it going to install?

Argh, now I see, it installs itself as the platform idle handler.

so cpuidle_install_idle_handler() pokes at the unmanaged pm_idle pointer
to make cpuidle take control.

On module load it does:

pm_idle_old = pm_idle;

then in the actual idle loop it does:

if (!dev || !dev->enabled) {
if (pm_idle_old)
pm_idle_old();
who is to say that the pointer stored at module init time is still
around at that time?

So cpuidle recognised the pm_idle stuff was a flaky, but instead of
fixing it, they build a whole new layer on top of it. Brilliant.

/me goes mark this whole thread read, I've got enough things to do.


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