Fedora power management

[David Zeuthen]

Hi,

On Fri, 2004-11-12 at 20:41 +0000, Hughes R Mr (UG - Electronic Eng)
wrote:
> Has this been done before? Or is it worth discussion? I thought I
> would try you guys at f-d-l and then try the gnome people when I know
> more good ideas/case studies.
> 

I think a better approach might be to teach hal about ACPI (for x86 and
others), PMU (for PowerMac's etc.) and provide an abstraction using the
functionality already in hal (e.g. properties on hal device objects and
callouts, device information files). This abstraction should be made
sufficiently extensible such that it may support more than ACPI and PMU
as well as the varying features on different laptops [1].

 http://freedesktop.org/pipermail/hal/2004-July/000555.html

Nothing really happened, though. Now that FC3 is out I hope to find some
time to do this for FC4 - it shouldn't be too difficult.

An interesting question is how we allow the desktop session to say "put
the system into standby". One trivial idea is to provide a 'system-
suspend' command (through consolehelper or something), however I think
that it might make more sense to make the hal daemon expose a D-BUS
interface with the appropriate methods - e.g. perhaps just the method
Suspend() on an interface org.freedesktop.Hal.Device.PowerManagement.

This method call should map to an appropriate script. That way we can
leverage the D-BUS policy system for allowing/denying this action [2].
Plus, that we'll need this in HAL anyway for other kind hardware/actions
(e.g. Rename() and Eject() on storage volumes) and it makes it somewhat
easier to use from e.g. GNOME applets.

Cheers,
David

[1] : Some laptops doesn't turn off the display when the lid is closed
(my Powerbook 12" for instance); tablets PC's probably don't have a lid
at all etc.

[2] : which may be as simple as only allowing an authorized user at the
console to perform the action.