Re: cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP]

Mark Gross
2006-09-11T23:50:25Z

On Tue, Sep 12, 2006 at 01:05:29AM +0200, Pavel Machek wrote:
> Hi!
>
> (cc-ed to lkml).
>
> > >>Just as a data point, "keeping the cpufreq interface" is
> > >>irrelevant to a number of us, because we configure it out
> > >>of the system. I'm not really arguing that we should get
> > >>rid of an existing kernel interface, but I don't see any
> > >>reason why we shouldn't be able to have a separately
> > >>configurable interface if cpufreq doesn't meet our needs.
> > >
> > >Configurable interfaces are evil,
> > Are you saying that not having sysfs attribute nodes for entities which
> > don't exist in a certain configuration is evil?
>
> I'm saying that
>
> #ifdef CONFIG_FOO
> provide user<->kernel interface
> #endif
>
> is evil.
>

I disagree.

> > >patch. You have developed your own little interface that suits your
> > >needs -- and that's fine -- but now you are trying to push it into
> > >mainline... and that is not, because those interfaces were not really
> > >designed to work together.
>
> > once cpufreq userland interface functionality which does not belong to the
> > kernel is moved out of the kernel cpufreq interface becomes a subset of
> > PowerOP sysfs interface. In other words this means that improvements of PM
> > stack layers/interfaces design will allow to design/develop an universal
> > userspace interface. We'd prefer to move gracefully in this direction
> > though.
>
> <tongue-in-cheek warning>
>
> Yes, once cpufreq userland interface is removed from kernel, merging
> powerop is reasonable thing to do. But please get at least
> Documentation/feature-removal-schedule.txt patch merged to mainline
> before attempting next powerop submission :-P.
>
> <I'm trying to explain that removing cpufreq userland interface is
> about as probable as MS Linux, and only a bit less likely than hell
> freezing over.>

The PowerOP patch has nothing to do with the removal of cpufreq. You
may be confusing this work with the david signleton patch.

--mgross