On a couple of Linux laptops I have the built in screen never turns off it's backlight, regardless if a 'black screen' sort of screen saver is activated (this both for a laptop running an X-based desktop as well as for a laptop only having a text console) or if I even close the lid of the laptop (looking carefully in the dark, I can tell that the screen still has the backlight on, even if the laptop "know" it is closed).
This is a bad thing for a couple of reasons:
It wastes power
It generates heat which when the laptop lid is closed increases the cooling need (the fan goes on more often etc).
Backlights have limited lifetime like all electric components and IIRC, the less a backlight is turned on, the longer it will last.
So, what is the best approach (considering a Gentoo with a 2.6.36 kernel) to remedy this? I recon that there probably are two approaches:
- one for text-only laptops which never displays a desktop, e.g a laptop sitting there acting like a firewall or server
- one for those running a Gnome/KDE/XFCE desktop (and a SLIM or GDM display manager).
The laptops I have in mind is a Dell Latitude CPi (built 1999, yes, it is from another millenea), a Compaq Armada M700 (built 2001) and a Dell Latitude D630.
If this can be accomplished only by configuring things in the Linux OS (be it kernel setup or editing config files) without touching anything in BIOS, that would of course be preferable.