power management with pbbuttonsd on older iMac

[Paul Robert]

I've seen a lot of people asking the same question, but no clear 
answers: How does one access power management options on YDL (using 
Gnome, let's say)? pbbuttonsd seems to promise what I'm looking for 
(brightness, contrast control, trigger sleep mode) but only on laptops. 
I have YDL 5.0.1 running on a 2001 iMac DV (bubble model), not a laptop. 
Can pbbuttonsd be of any use? Any time I try to run pbbuttonsd, I get 
this message:
> WARNING: No backlight driver available - check your Kernel configuration.
> INFO: Initialized: ALSA Mixer
> pbbuttonsd 0.8.0: Unknown PowerBook - PMU version: 12
> INFO: Script '/etc/power/pmcs-pbbuttonsd performance ac ' lauched but 
> exitcode is not null
Obviously powerprefs, (GUI for pbbuttonsd) doesn't work either:
ERROR: Server message port not found. Server isn't running.

Anybody have suggestions?