Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

Pavel Machek
2006-09-11T21:00:26Z

> >>- PowerOP is only one layer (towards the bottom) in a power management
> >>solution.
> >>- PowerOP does *not* replace cpufreq
> >
> >PowerOP provides userland interface for changing processor
> >frequency. That's bad -- duplicate interface.
> Basically the biggest problem with cpufreq interface is that cpufreq has
> "chose
> predefined closest to a given frequency" functionality implemented in the
> kernel while there is _no_ any reason to have this functionality
> implemented in
> the kernel if we have sysfs interface exported by PowerOP in place - you
> just

No, there is reason to keep that in kernel -- so that cpufreq
userspace interface can be kept, and so that resulting kernel<->user
interface is not ugly.

> of the fact that cpufreq implements incorrect design of PM stack layers and
> interfaces. PowerOP solves this issues as well.

Actually I believe that cpufreq implements correct design and PowerOP
got it wrong.

> >Well, you'll only get good interface review when you have
> >Documentation/ , and it needs to go to lkml before it goes to any
> >queues.
> PM stack is too complex and heavy part to go in such pieces thru lkml. i
> expect all linux pm experts to be on this list

"We are too lazy to make the code clean enough / well enough explained
to survive lkml review".

Your interface impacts everyone, so everyone should have chance to
comment on it.
Pavel
--
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