[Utopia] ACPI and DBUS integration

[Matthew Garrett <mjg59-utopia srcf ucam org>]

Daniel Silverstone (not to be confused with Daniel Stone) has hacked up 
a nice little app that gets called by acpid and sends dbus events 
whenever an acpi event is received. At the moment, this will be whenever 
an ACPI button is pressed or there's a power state change.

This probably isn't the long term goal. At present, the way this works 
is for acpid to get an acpi event and turn that into some sort of state 
change, so you'll get "button/sleep" rather than "transitioning to S3 
sleep". In the long run, acpid probably needs to be reimplemented so 
it's a little bit more intelligent than just running scripts that can do 
anything.

The Utopian consequences ought to be fairly clear. Suspending a laptop
should result in it coming back with the screen locked. Closing the lid
should trigger screen blanking even if it doesn't suspend (this is done
in hardware on some machines, but not all of them). Movie applications
ought to be prompted that I'm on battery and consider whether a lower
quality but less CPU intensive algorithm would be helpful. When I get to
low battery levels, applications should be more paranoid about
autosaving work (yeah, this ends up consuming more power, but still). 
Countless others.

The tarball's at http://users.pepperfish.net/dsilvers/acpi-dbus.tar.bz2 
- make, make install and follow the instructions. Requires acpid to be 
installed.

-- 
Matthew Garrett | mjg59 srcf ucam org