I have a problem with my Toshiba Satellite R850.
The brightness-adjustment via the Function-Keys and the system settings works properly, but not after putting the Laptop on Sleep-Mode.
The answer given in this thread did the trick for me with Ubuntu 12.10 64-Bit, but doesn't seem to work with Ubuntu 13.04 64-Bit.
Has anyone experienced the same and know a workaround for this?