Re: [RFD] Automatic suspend

Pavel Machek
2009-02-27T10:09:41Z

Hi!

> > > Then, the decision making logic will be able to use /sys/power/sleep whenever
> > > it wishes to and the kernel will be able to refuse to suspend if it's not
> > > desirable at the moment.
> > >
> > > It seems to be flexible enough to me.
> >
> > This seems flexible enough to avoid race conditions, but it forces the
> > user space power manager to poll when the kernel refuse suspend.
>
> And if the kernel is supposed to start automatic suspend, it has to monitor
> all of the wakelocks. IMO, it's better to allow the power manager to poll the
> kernel if it refuses to suspend.

polling is evil -- it keeps CPU wake up => wastes power.

Wakelocks done right are single atomic_t... and if you set it to 0,
you just unblock "sleeper" thread or something. Zero polling and very
simple...
Pavel
--
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