Re: [linux-pm] [RFC] input: syfs switches for SKE keypad

Alan Stern
2010-10-06T18:19:03Z

On Wed, 6 Oct 2010, Dmitry Torokhov wrote:

> > > I think last time Rafael mentioned that runtime PM did not allow for
> > > forcing power state from userspace but I wonder if it would be possible
> > > for userspace to signal and "accelerate" the idle state for a device and
> > > then standard runtime PM framework would kick in...
> >
> > Yes; drivers can implement their runtime power policy any way they
> > want. For example, a driver could create a sysfs attribute file which
> > userspace could use to ask for changes in the power state.
> >
> > The real question is whether the driver is platform-specific. If it is
> > then fine, it can do whatever it wants. If it isn't then it should
> > try to avoid doing things that are tied to a specific platform.
> >
>
> No, I really think it is wrong. This what leads us to the situation we
> are in at the moment. Every device [re]implements its own little knobs
> to do power management. Accelerometers export their (often tailored to a
> specific platform) attributes in sysfs in nonstandard way. And so on,
> and so forth.
>
> Here I'd like to see these (PM) hooks done on device core level, i.e.
> the knobs should be unified and live in /sys/devices/.../deviceX/power/

I haven't followed this thread in detail. What sort of knobs are you
talking about? That is, what needs to be done? Maybe the PM core
already provides these features.

Alan Stern