Back to main blog list.

Asus backlight on KDE4

Date: Saturday 30 March 2013
Changed: Saturday 30 March 2013

I have an Asus Laptop A55VD and it took me some time to get the backlight working. That was quite an issue because on battery power the battery was quickly drained if the backlight was on full brightness.

Having a look in /sys/class/backlight I had acpi_video0 and acpi_video1.

After changing the kernel command line to include:

acpi_backlight=vendor

I had two devices in /sys/class/backlight:

asus-nb-wmi and intel_backlight

The intel_backlight interface worked, but the asus-nb-wmi-interface not, but KDE4 insisted on using the asus-nb-wmi-interface.

So finally decided to blacklist the asus-nb-wmi kernel module; According to the explanation this module is supposed to make certain hotkeys working, but I haven't found any hotkeys which stopped working after unloading this module.

The Fn+Brightness++ and Fn+Brightness-- buttons didn't work with or without the kernel-module.

So without this module loaded I have only left intel_backlight in /sys/class/backlight and KDE4 is using it.