Backlight Control for Debian

[reed9]

You don't have contrib enabled in any of these, which is probably why the dependency problems. You may want non-free as well.

deb http://mirrors.kernel.org/debian/ lenny main contrib non-free

Add to the security and volatile mirrors as well.

Try reinstalling xbacklight, hotkeys, and hotkey-setup.

[nujinini]

After I added contrib non-free to the three, I made a reboot just to make sure.

Here is my output.

jun@debian:~$ su -
Password:
debian:~# apt-get install xbacklight
Reading package lists... Done
Building dependency tree
Reading state information... Done
xbacklight is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
debian:~# exit
logout
jun@debian:~$ xbacklight -dec 10%
No outputs have backlight property

[reed9]

Do you have acpid installed?

su -
apt-get install acpid

What kind of computer is this? Make/Model?

Do you have anything in the directory /sys/class/backlight?

[nujinini]

jun@debian:~$ su -
Password:
debian:~# apt-get install acpid
Reading package lists... Done
Building dependency tree
Reading state information... Done
acpid is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
debian:~#

Its a Lenovo G4300-3000, laptop

debian:~# ls /sys/class/backlight
acpi_video0  acpi_video1
debian:~#

[reed9]

ls /sys/class/backlightacpi_video0/

Does this return max_brightness, actual_brightness, and brightness?

If brightness is there try

echo 20 > /sys/class/backlight/acpi_video0/brightness

You'll probably need to be root for that.

Replace "20" with other numbers as desired. I believe the range is 0 to 100, from darkest to lightest, but I couldn't find confirmation of that.

[nujinini]

jun@debian:~$ ls /sys/class/backlightacpi_video0/
ls: cannot access /sys/class/backlightacpi_video0/: No such file or directory
jun@debian:~$ su -
Password:

debian:~# ls /sys/class/backlightacpi_video0/
ls: cannot access /sys/class/backlightacpi_video0/: No such file or directory
debian:~#

Not so good results

[reed9]

I initially made a typo, which I corrected, but I'm guess you're going off the original email notification contents.

/sys/class/backlightacpi_video0/

should be

/sys/class/backlight/acpi_video0/

[nujinini]

debian:~# ls /sys/class/backlight/acpi_video0/
actual_brightness  brightness      power      uevent
bl_power           max_brightness  subsystem
debian:~#

I guess this output is promising?

[nujinini]

I tried to change 20 to 10 but still no backlight change

debian:~# echo 10 > /sys/class/backlight/acpi_video0/brightness
debian:~#