I'm having the same problem with my Acer Aspire 7736z (it's old, I know) and Mint 14 (Cinnamon 1.6.7) (64-bit).
I tried the solution nilan suggested, but each time, the package cannot be located. I did an update before trying to install, and tried aptitude and apt-get just in case.
nilan wrote:$ sudo aptitude install cedarview-graphics-drivers
I was able do find a deb file on Ubuntu's website, but I get an error with that:
Error: Dependency is not satisfiable: cedarview-drm
One thing that I've noticed that I hope may be of some help to finding a more universal solution is that during boot - and specifically while the BIOS is loading, or when the GRUB is displayed - the hardware keys for brightness work! They work perfectly, but then at some point after the GUI loads, this functionality disappears!
I hope that little clue will help some one smarter than I figure this out, or maybe some one could help me get the cedarview drivers installed.