I have tried many potential solutions but to no avail! (this is going to be a long post) Essentially, when I first install ubuntu (I have tested 10.11-12.04 beta) I can change the brightness of the macbook backlight. One of the first things I usually do once my machine finishes installing is enter "sudo apt-get install nvidia-current" into the terminal to get my Nvidia graphics card set up. Before I install nvidia-current power management works flawlessly. After installing nvidia-current my graphics driver works mostly properly (more on that later). When I press F1 or F2 notify osd pops up and shows icon for the backlight along with a meter which changes according to how much I press F1 or F2, but the backlight does not change brightness at all. Two supplementary facts: when I am running off of battery power the backlight does not dim ever, also changing the backlight brightness through the terminal does not work (it recognizes the command but changes nothing).

Things which did not work: 1. editing xorg.conf 2. python script/hack 3. editing grub

Things which did work: 1. removing Nvidia-Current

Final piece of information: Although my graphics card works in every way but Power Management it can not be found through System Settings/Details (Graphics Unknown) I'm using the NVIDIA GeForce 320M. the output of lspci is:

00:00.0 Host bridge: NVIDIA Corporation MCP89 HOST Bridge (rev a1) 00:00.1 RAM memory: NVIDIA Corporation MCP89 Memory Controller (rev a1) 00:01.0 RAM memory: NVIDIA Corporation Device 0d6d (rev a1) 00:01.1 RAM memory: NVIDIA Corporation Device 0d6e (rev a1) 00:01.2 RAM memory: NVIDIA Corporation Device 0d6f (rev a1) 00:01.3 RAM memory: NVIDIA Corporation Device 0d70 (rev a1) 00:02.0 RAM memory: NVIDIA Corporation Device 0d71 (rev a1) 00:02.1 RAM memory: NVIDIA Corporation Device 0d72 (rev a1) 00:03.0 ISA bridge: NVIDIA Corporation MCP89 LPC Bridge (rev a2) 00:03.1 RAM memory: NVIDIA Corporation MCP89 Memory Controller (rev a1) 00:03.2 SMBus: NVIDIA Corporation MCP89 SMBus (rev a1) 00:03.3 RAM memory: NVIDIA Corporation MCP89 Memory Controller (rev a1) 00:03.4 Co-processor: NVIDIA Corporation MCP89 Co-Processor (rev a1) 00:04.0 USB controller: NVIDIA Corporation MCP89 OHCI USB 1.1 Controller (rev a1) 00:04.1 USB controller: NVIDIA Corporation MCP89 EHCI USB 2.0 Controller (rev a2) 00:06.0 USB controller: NVIDIA Corporation MCP89 OHCI USB 1.1 Controller (rev a1) 00:06.1 USB controller: NVIDIA Corporation MCP89 EHCI USB 2.0 Controller (rev a2) 00:08.0 Audio device: NVIDIA Corporation MCP89 High Definition Audio (rev a2) 00:09.0 Ethernet controller: NVIDIA Corporation MCP89 Ethernet (rev a1) 00:0a.0 IDE interface: NVIDIA Corporation MCP89 SATA Controller (rev a2) 00:0b.0 RAM memory: NVIDIA Corporation Device 0d75 (rev a1) 00:15.0 PCI bridge: NVIDIA Corporation Device 0d9b (rev a1) 00:17.0 PCI bridge: NVIDIA Corporation MCP89 PCI Express Bridge (rev a1) 01:00.0 Network controller: Broadcom Corporation BCM43224 802.11a/b/g/n (rev 01) 02:00.0 VGA compatible controller: NVIDIA Corporation Device 08a0 (rev a2)

There is a very similar bug on Launchpad which I have posted below. https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers/+bug/764195