After upgrading from 12.10 to 13.04 the brightness control buttons on my laptop(Lenovo E430) are not working properly - when I try to brighten the screen, nothing happens, but when I try to dim the screen, the screen immediately dims to the lowest possible setting. I am then not able to change the brightness back up with the brightness control buttons and have to open Brightness & Lock settings to set it back up, where it works...
I have a Lenovo E430 and I ran into the same issue. I posted on the UbuntuForums and a friendly user helped me out. The original post is here.
These are the steps I followed:
- sudo gedit /etc/default/grub (I know the link says gksu but it said not installed or something when I tried it, so I just used sudo)
- Look for the line that says GRUB_CMDLINE_LINUX="" and change it to this: GRUB_CMDLINE_LINUX="acpi_osi=\"!Windows 2012\""
- sudo update-grub
After that my brightness controls with the keys worked fine.
Note: Before (and after) I did this, I was still able to change the brightness via the slider found in "Brightness and Lock" within System Settings. It was how I worked around the lack of function keys doing their job until a user helped me with this solution.
Hope this helps!