[linux-pm] [RFD] Automatic suspend

[Rafael J. Wysocki]

On Monday 16 February 2009, Alan Stern wrote:
> On Mon, 16 Feb 2009, Rafael J. Wysocki wrote:
> 
> > OK, so I think there are two things that user space may be allowed to do as
> > far as putting devices into low power states is concerned:
> > * disable/enable the automatic power management of the device (provided that
> >   the driver supports the automatic PM)
> 
> Set the automatic PM parameters (idle timeout, state to go to, etc.).  

Yes.  I'm not sure about the state part, though.

> And disabling automatic PM altogether (effectively the same as setting
> the idle timeout to infinity).

Yes.

> > * check what power states devices are in.
> 
> What about situations where we want to distinguish between the power 
> state of the device itself and the power state of the link?  For a disk 
> drive we may want to power the link on and off quite a lot, as that 
> has low latency, but spinning the disk up and down takes a long time 
> and so should have a longer idle-time value.

Well, I'm not sure at the moment.

Do you have any suggestions?

Rafael