[gpm] Suspending laptop as user

[Chris Vine <chris cvine freeserve co uk>]

I use gnome-2.16.1, with gnome-power-manager-2.16.1, dbus-0.93, 
dbus-glib-0.71, hal-0.5.8.1 and libnotify-0.4.3 with a vanilla linux 2.6.18 
kernel.  hal is compiled with the policy kit disabled (so it should accept 
anything from anyone).  The kernel is configured to allow acpi sleep.

The kernel suspend is working fine, as I can suspend my laptop as root with 
echo -n mem > /sys/power/state, and if I am logged into GNOME as root I can 
also suspend the laptop successfully via gnome-power-manager.  However, 
gnome-power-manager fails to suspend if I am logged in as an ordinary user.  
(As user, I have to su root in a terminal and write directly 
to /sys/power/state in order to suspend.)

This seems to be a permissions issue.  I know very little about configuring 
dbus, hal or gnome-power-manager.  Is there a way in which I can configure 
all or any of them to allow a user to suspend via gnome-power-manager?

Chris