I'm trying to use Linux on a Toshiba P855 laptop. And I have one big problem: the screen brightness can't be changed, and stays at maximum.

Tried different distros, also tried many boot options in the /etc/default/grub file, but no success. Currently I'm with Kubuntu 12.04, and the function keys for brightness don't work (they never did on any distro), so I'm able to use only the slider for the brightness. But even then - nothing really changes.

All is working on Windows. What's wrong here?

I'm trying to use Linux on a Toshiba P855 laptop. And I have one big problem: the screen brightness can't be changed, and stays at maximum.

Tried different distros, also tried many boot options in the /etc/default/grub file, but no success. Currently I'm with Kubuntu 12.04, and the function keys for brightness don't work (they never did on any distro), so I'm able to use only the slider for the brightness. But even then - nothing really changes.

All is working on Windows. What's wrong here?

EDIT: Additional information

Well, in /sys/class/backlight I have a symlink:

toshiba -> ../../devices/LNXSYSTM: 00/TOS1900:00/backlight/toshiba/

and in that toshiba folder I have:

• actual_brightness

• bl_power

• brightness

device -> ../../../TOS1900:00/

• max_brightness

• power (folder)

• subsystem -> ...

• type

• uevent

and in /proc/acpi/ I have:

• ac_adapter (folder)

• battery (folder)

• button (folder)

• event

• toshiba (folder)

• wakeup

guys ... and eventually chicks :) ...

I have Toshiba P855 laptop with pre-installed Windows 7, but I'm mostly Linux fan ... so I'm trying to use linux on it. And I have one big problem: the screen brightness can't be changed, and stays at maximum.

Tried different distros, also tried many boot options in the /etd/default/grub file, but no success. Currently I'm with Kubuntu 12.04, and the function keys for brightness don't work (they never did on any distro), so I'm able to use only the slider for the brightness. But even then - nothing really changes :( ...

All is working on Windows.

Can you help me? ...

(I didn't expect this laptop will be sooooooo much tightly made for Windows :(( ...)

I'm trying to use Linux on a Toshiba P855 laptop. And I have one big problem: the screen brightness can't be changed, and stays at maximum.

Tried different distros, also tried many boot options in the /etc/default/grub file, but no success. Currently I'm with Kubuntu 12.04, and the function keys for brightness don't work (they never did on any distro), so I'm able to use only the slider for the brightness. But even then - nothing really changes.

All is working on Windows. What's wrong here?