I am not able to change the screen brightness on lenovo z570.
Even the function keys for the brightness are also not working. Any idea ?
If all else fails, you might want to try out the command line utility xbacklight.
You can install it by running
Then if you want to make the screen brighter you can type
(or replace 50 with whatever percentage you'd like)
Or if you wanted to dim the screen you can type
Also if you really had the time, you might want to mess with keybindings to make running those commands more convenient.
Try switching off Num Lock.
With my z570 xubuntu the brightness keys are without function if Num Lock is active. When i switch it off every thing works fine.
Try the following and see if after a reboot your brightness keys are functional again.
Edit etc/X11/xorg.conf and add the another line to the Device section: