My samsung R730 will not change the backlight brightness in Mint, either by the function keys or via power settings, etc... It does however work at the grub screen, and the brightness set there will carry over to mint.
I have tried every suggestion I can find - nomodeset, acpi_osi=Linux, acpi_backlight=vendor, using xrandr - but no luck. Mint thinks there is a backlight, but changes to the brightness values aren't reflected in the hardware (acpi_backlight was interesting, it stopped mint from even detecting the backlight).
I have no idea where to go from here. Does anyone have any genius ideas, or know how I could go about isolating where the problem is? I'm running Mint 9, kernel 2.6.32-21.