Changing brightness.

Gentooser · n00b Joined: 11 Mar 2009 Posts: 16

Helllo,
I've got a problem with changing brighness of my screen.
I have special keys on my laptop: brightness down and brightness up.
When I press one of them, there is no effect untill I turn my screen off and on again... It's a bit annoying...
Any ideas how to fix it ?

I have geforce 9600 with driver 180.29.

Cheers.

ewaller · Posted: Sun Mar 29, 2009 12:03 am Post subject:

Backlight brightness on laptops can be a challenge.

It is usually controlled by one of the power management functions. Most modern systems use ACPI. Take a look in /proc/acpi and see if there are any files related to brightness. If there is, try something like, cat the contents of the file and see if it tells you the current brightness setting. To change it, try:

Gentooser · n00b Joined: 11 Mar 2009 Posts: 16

Couldn't find it in /proc/acpi, but have found it in:
/sys/devices/platform/acer-wmi/backlight/acer-wmi.

There are several files, e.g.
actual_brightness 9
brightness 9
max_brightness 9
bl_powers 0

these numbers are returend when sending command "cat xxx".

when I press the brithness up/down buttons, value of actual_brightness changes but I still need to turn off and on my screen to see an effect...

d2_racing · Posted: Sun Mar 29, 2009 2:27 pm Post subject:

Hi, you should enable Video inside the ACPI and the event option inside the device driver,section input.