I'm having problems with my laptop backlight on my Acer Aspire 5100 running Ubuntu 32bit 10.10: The backlight won't switch off according to power management settings. The display goes black like it should, but the light stays on.

Command "xset dpms force off" works just fine and the light turns off. So does Fn+F5 combination and closing the lid, but I want that light to turn off automatically like it did on win xp.


I actually even tried and edited one of the screensavers to make it execute the command:

/usr/share/applications/screensavers/glblur.desktop
Code:
[Desktop Entry]
Name=glblur
Exec=/usr/bin/xset dpms force off
TryExec=/usr/bin/xset
Comment=Turn off backlight
StartupNotify=false
Terminal=false
Type=Application
Categories=GNOME;Screensaver;
OnlyShowIn=GNOME;
...and copied all this into /usr/share/applications/desktop.*_*.utf8.cache as well to make it update the settings.

But this does not turn off the backlight when the screensaver delay has passed. Screen does slowly fade to black (like with all the screensavers) but the backlight stays on


So,

* How can I fix the power saving function so that it would also turn off the backlight?

or

* How could I set xset dpms force off to run when the computer has been idle for some time? cron?

or

* How can I make xset dpms force off work from a screensaver file?


I'm getting really desperate with this..