How do I get the brightness buttons on a Dell Inspiron N4010 working?

Question

After 13.04 update the brightness control and even brightness in setting have stopped working. The brightness is on full and doesn't decrease. So far sound and wifi is working. Any settings or parameters that can be useful ? Even on suspend laptop is not going on sleep mode. This was working on 12.10

Answer 1

Try using this boot parameter apci_osi='!Windows 2012'
Command:

`sudo sed -i "s/quiet splash/quiet splash acpi_osi=\'\!Windows 2012\'/" /etc/default/grub;sudo update-grub`

if it makes things worse run this

`sudo sed -i "s/ acpi_osi=\'\!Windows 2012\'//" /etc/default/grub;sudo update-grub`