tags:
Ubuntu 12.04, 12.10, 13.04, Linux, Opensource,lenovo, acer, Acer
Aspire, Brightness fix, Cannot reduce Brightness,
open /etc/default/grub
sudo gedit /etc/default/grub
and change
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
then do
sudo update-grub
and reboot the system.