I recently installed Ubuntu 14.04 LTS on my Sony Vaio [nVidia GeForce 410M/PCIe/SSE2]. Earlier I had 12.04 installed on it, then I edited the xorg.conf file to control brightness using the function keys. But now the file is empty and even if i created it like last time it ain't working. I tried the xbacklight too, it didn't worked.
EDIT: Ubuntu Installed is 64bit version.