I had Ubuntu 12.10 on my PC, and I did the upgrade to Ubuntu 13.10. But now I have a problem with brightness control, it is always on maximum level and I can't set it neither with fn nor with brightness control in the system settings nor with
xbacklight or other method.
I had tried changing
GRUB_CMDLINE_LINUX_DEFAULT value, but nothing happens.
How can I fix this problem?
I have ubuntu 13.10 64bit, kernel 3.11.0-13, on a Toshiba Portege R930, Processor: Intel® Core™ i7-3520M CPU @ 2.90GHz × 4; Graphic: Intel® Ivybridge Mobile