sudo sed 's/GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"/GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="/' -i /etc/default/grub
http://askubuntu.com/questions/230609/brightness-keyboard-buttons-do-not-work-on-asus-1225c
sudo sed 's/GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"/GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="/' -i /etc/default/grub
http://askubuntu.com/questions/230609/brightness-keyboard-buttons-do-not-work-on-asus-1225c