This is an attempt at a generic PM event interface for the kernel.
The design is more or less obvious and was laid out in a previous
message. Comments appreciated.

Alan Cox <alan@lxorguk.ukuu.org.uk> writes:

> > > The entire PM layer for the embedded board I worked on was
> > > 3Kbytes. How small will yours be 8)
> > 
> > The generic event interface will be under 3kB, I hope. Would you
> > accept it if so? ;-)
> 
> We shall see. I've played with several ideas and never really been
> happy with them so maybe you can solve it

The fruits of today's labour are here. Unfortunately it *is* just over
3kB (but if I understand correctly under 4kB) mostly due to the
generous buffer sizes.

Note that this is prelim work. (Particularly the changes to the APM
stuff need to be looked at, and are not strictly relevant to the patch
at hand.) At the moment, APM events are printed to /dev/pmevent and
kmsg. Suspend requests are no longer acted on by the kernel. This
breaks backward compatibility.

The /dev/pmevent stuff is hopefully pretty feature complete. The
device numbers for it are 10 137. Multiple listeners are allowed etc.