Howto Lower brightness on Apple LCD Monitor? KUbuntu 10.4, KDE System Settings Display; jor XOrg

[Éric Piel]

Op 22-06-10 23:56, giovanni_re schreef:
> Didn't get an answer on KUbuntu list, so hopefully someone here might
> have a suggestion.
> 
> ==
> I've just installed an Apple Cinema Display (LCD) monitor. This is a 5
> year old monitor.
> Using KUbuntu 10.4
> 
> The apple website indicates this monitor has:
> User controls (hardware and software):
>   	Display power, system sleep, system wake, brightness and display tilt
> http://support.apple.com/kb/SP79
> http://support.apple.com/kb/SP77
> 
> Brightness is what I want to turn down.
> 
> Looking in the 
> KDE System Settings > General > Computer Administration > Display > Size
> & orientation > DVI-0
> 
> there is no adjustment for brightness.
> 
> Anyone know how to decrease brightness on this?
> 
> What sw manages the KDE system settings for Displays?  KDE? X?
> 
> Is there a way to turn down the brightness using some X config?
> 
> Is there a GUI for doing X configuration settings?

Why do you think you can change the brightness via software? It is very
unsual for separate monitors to support this. Isn't there some buttons
on the monitor to do that?!

Anyway, if you really want to do this by software:
 * DDC/CI is the key. Try using ddccontrol. But your graphic card must
support it, and your monitor too. In practice, it's unlikely to work.
 * You can _simulate_ a lower brightness by using xrandr "brightness"
option. See the manpage.

Eric