Dimming a laptop's backlight when idle

[Aaron Stone]

On Thu, 2006-02-02 at 09:39 -0500, David Zeuthen wrote:
> On Thu, 2006-02-02 at 01:42 -0800, Aaron Stone wrote:
> > Hi folks,
> > 
> > I've been hunting around for a while to try and find any previous work
> > on auto-dimming laptop backlights, and haven't found much at all.
> 
> FYI the combination of gnome-power-manager, gnome-screensaver and HAL
> does this already. It should be trivial to use this from other desktop
> environments too as setting (and getting) the brightness for back light
> for the LCD is carried out through an extensible abstract interface in
> HAL. Right now I think the interface supports IBM Thinkpad, Apple
> Powerbook + iBook, Toshiba, Panasonic, Asus, Sony. We take patches for
> other laptops. Btw, I do wonder if the X.org server should provide this
> interface instead.

I'm sure the KDE folks have figured something out, too. At the moment
I'm using XFCE, which is happy to handle systray plugins. So this might
Work Right Now (TM), but I don't think it's the Right Way To Do It (TM).

My ideal idea is that the DPMS settings for the X server should be
extended to the semantics of an LCD. The three DPMS modes are:
StandbyTime, SuspendTime and OffTime. These map nicely onto an LCD,
where the effects should probably be Dim, Dimmer, Off. Screensaver
timeouts run totally idependently, which is good.

I have absolutely no idea how this would be implemented. The hackish
approach might be DPMSStandbyCommand, DPMSSuspendCommand, etc. and have
a few little scripts or HAL commands or whatever do the dimming.

The benefit of putting it into the X server is that any screensaver
program that knows how to 'xset dpms' can control the backlight.

Aaron