Backlight no longer works on Macbook Pro5,5 with EFI boot

[Eric Miao]

After installed precise beta1 on Macbook Pro5,5 with EFI boot, (i.e. a GPT partitioned, /dev/sda1 20MB FAT partition for GRUB EFI boot loader under /EFI/ubuntu/grubx86.efi), backlight no longer works. Module apple_bl.ko inserted, but driver probe failed after trying to write to the intensity and read it back to verify if it's same value. This is most likely caused by booting from EFI.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-generic 3.2.0.17.17
ProcVersionSignature: Ubuntu 3.2.0-17.27-generic 3.2.6
Uname: Linux 3.2.0-17-generic x86_64
NonfreeKernelModules: nvidia wl
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.94.1-0ubuntu2
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: NVidia [HDA NVidia], device 0: Cirrus Analog [Cirrus Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: ycmiao 2170 F.... pulseaudio
CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211 not found.
Card0.Amixer.info:
 Card hw:0 'NVidia'/'HDA NVidia at 0xd3480000 irq 20'
   Mixer name : 'Cirrus Logic CS4206'
   Components : 'HDA:10134206,106b4d00,00100301'
   Controls : 18
   Simple ctrls : 9
Date: Mon Mar 12 11:02:42 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120301)
MachineType: Apple Inc. MacBookPro5,5
ProcEnviron:
 TERM=xterm
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-17-generic root=UUID=6da468bc-a989-4778-9e2c-56a3665c5e7b ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-17-generic N/A
 linux-backports-modules-3.2.0-17-generic N/A
 linux-firmware 1.71
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/15/09
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBP55.88Z.00AC.B03.0906151708
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-F2268AC8
dmi.board.vendor: Apple Inc.
dmi.chassis.asset.tag: Asset Tag#
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-F2268AC8
dmi.modalias: dmi:bvnAppleInc.:bvrMBP55.88Z.00AC.B03.0906151708:bd06/15/09:svnAppleInc.:pnMacBookPro5,5:pvr1.0:rvnAppleInc.:rnMac-F2268AC8:rvr:cvnAppleInc.:ct10:cvrMac-F2268AC8:
dmi.product.name: MacBookPro5,5
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.

[Brad Figg (brad-figg)]

Thank you for taking the time to file a bug report on this issue.

However, given the number of bugs that the Kernel Team receives during any development cycle it is impossible for us to review them all. Therefore, we occasionally resort to using automated bots to request further testing. This is such a request.

We have noted that there is a newer version of the development kernel than the one you last tested when this issue was found. Please test again with the newer kernel and indicate in the bug if this issue still exists or not.

You can update to the latest development kernel by simply running the following commands in a terminal window:

    sudo apt-get update
    sudo apt-get upgrade

If the bug still exists, change the bug status from Incomplete to Confirmed. If the bug no longer exists, change the bug status from Incomplete to Fix Released.

If you want this bot to quit automatically requesting kernel tests, add a tag named: bot-stop-nagging.

 Thank you for your help, we really do appreciate it.

[Seth Forshee (sforshee)]

Eric: You say "no longer works." When did it work? With a previous release? When booted in BIOS-compatibility mode? You're sure it was using apple_bl when it did work?

Does nouveau work with EFI boot? If so, it's backlight control may work. If not, the mactel support PPA has a mbp-nvidia-bl-dkms package which essentially implements the backlight support from nouveau, which may be worth trying. I know that on some models backlight adjustment is available through the graphics card, but the binary-only nvidia driver does not implement backlight control afaik.

[Eric Miao (eric.y.miao)]

@Seth, after updating gnome-settings-daemon to 3.3.91-0ubuntu3, the backlight is now working with nouveau driver w/ EFI boot. Verified that apple_bl.ko never worked correctly. Mark this bug duplicate of #947748.