[gpm] Controlling LCD backlight (nouveau driver) through Gnome power management

[leonardo davinci <leonadavinci gmail com>]

Hello,

I  have a gnu/linux box (Linux myhost 2.6.33-ARCH #1 SMP PREEMPT Mon
Apr 5 05:57:38 UTC 2010 i686 Intel(R) Core(TM)2 Duo CPU T7100 @
1.80GHz GenuineIntel GNU/Linux) with Gnome 2.30 installed. My computer
is a laptop SONY VAIO VGN-AR41L. The laptop uses an nvidia 8400M GT
graphics card. I have successfully installed the nouveau driver (2D
mode) instead of nv and all the other daemons like hal,acpi,pm-utils.
The laptop can suspend when I close the lid or when I am pressing the
"Suspend" button from the GNOME interface. The laptop has also two
combinations for controlling the backlight . The Fn+F5 for decreasing
and Fn+F6 for increasing. Now about my subject. When I am pressing one
of the above combinations the GNOME shows a progress bar to notify
that the user changes the brightenss and to show the amount of change,
but the brightness does not change. I have found the reason and I want
a help to find a solution. The reason is that the file
/sys/class/backlight/sony/brightness is modified
instead of /sys/class/backlight/nv_backlight/brightness. If I give an
"echo command" '''a number between 500 to 1025''' and redirect the
output to the /sys/class/backlight/nv_backlight/brightenss then the
brightness changes accordingly. A temporary solution that I gave was
to create a little daemon backlightd (which you can find in
http://sourceforge.net/projects/backlightd/, the daemon was created
when I had Fedora 12 but know I am having Archlinux and the daemon
works) but I want a more permanent solution. I want to modify GNOME
Power Management in order to do the same job for me and for the rest
of the community of course. I don't know if this has to do with the
GNOME Power Management or with ACPI,HAL or something else.

I am looking forward to hearing from you
LD