Brightness on Acer E1-570

In a thread on http://www.linlap.com/acer_aspire_e1-571 Jan gives this solution:

 I had the same problem and found this solution in “http://www.askubuntu.com”:

Try editing /etc/default/grub with the following values:

Open a terminal and type sudo gedit /etc/default/grub.

First try changing the line that reads:

GRUB_CMDLINE_LINUX_DEFAULT=“quiet splash” to

GRUB_CMDLINE_LINUX_DEFAULT=“quiet splash acpi_backlight=vendor”

Then save, close gedit and type sudo update-grub and reboot the computer.