I recently installed Linux Mint 14 on my Samsung R580 laptop. The Fn-keys worked out of the box, I can switch screens, adjust volume and so on.
When I try to adjust the brightness (Fn + ↑/↓), the slider shows up and moves to the left and right, but screen brightness does not change at all, it always stays at 100%.
I tried to change the brightness in the system settings and it also doesn't do anything.
When I'm inactive for 5-10 minutes, the energy saving profile kicks in and the screen is dimmed. So the dimming does work, but not when I change it manually.
I found some threads stating that you should change the acpi_background setting to "vendor" in Grub config, but that didn't change anything for me.
What else can I try?