Brightness
sudo gedit /etc/default/grub
find this
line : GRUB_CMSLINE_LINUX_DEFAULT="quiet splash"
change
to: GRUB_CMDLINE_LINUX_DEFAULT=
"quiet splash
acpi_backlight=vendor"
and save it
then cmd > sudo
update-grub
原文：http://www.cnblogs.com/xfile/p/3736254.html