LCD backlight level is reset to maximum after a reboot.

[Li Li]

Happened on the latest Ubuntu Precise on MacbookAir 4,1.

I have to adjust the LCD backlight each time Ubuntu is rebooted manually - or the LCD hurts my eyes.
---
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.90-0ubuntu1
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: PCH [HDA Intel PCH], device 0: Cirrus Analog [Cirrus Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: lli5 1648 F.... pulseaudio
Card0.Amixer.info:
 Card hw:0 'PCH'/'HDA Intel PCH at 0x90600000 irq 47'
   Mixer name : 'Intel CougarPoint HDMI'
   Components : 'HDA:10134206,106b6200,00100302 HDA:80862805,80860101,00100000'
   Controls : 25
   Simple ctrls : 9
DistroRelease: Ubuntu 12.04
HibernationDevice: RESUME=UUID=cc35910e-72f8-4156-85f0-acfc48012f31
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64+mac (20120108)
MachineType: Apple Inc. MacBookAir4,1
NonfreeKernelModules: wl
Package: linux (not installed)
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-8-generic root=UUID=02e7076b-bab1-4657-ae2c-d6c733869f1c ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 3.2.0-8.15-generic 3.2.0
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-8-generic N/A
 linux-backports-modules-3.2.0-8-generic N/A
 linux-firmware 1.67
StagingDrivers: mei
Tags: precise running-unity staging
Uname: Linux 3.2.0-8-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
dmi.bios.date: 10/14/2011
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBA41.88Z.0077.B0E.1110141154
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-C08A6BB70A942AC2
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookAir4,1
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-C08A6BB70A942AC2
dmi.modalias: dmi:bvnAppleInc.:bvrMBA41.88Z.0077.B0E.1110141154:bd10/14/2011:svnAppleInc.:pnMacBookAir4,1:pvr1.0:rvnAppleInc.:rnMac-C08A6BB70A942AC2:rvrMacBookAir4,1:cvnAppleInc.:ct10:cvrMac-C08A6BB70A942AC2:
dmi.product.name: MacBookAir4,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.
---
.tmp.unity.support.test.0:

ApportVersion: 1.90-0ubuntu1
Architecture: amd64
CompizPlugins: [core,bailer,detection,composite,opengl,decor,compiztoolbox,grid,vpswitch,mousepoll,place,resize,regex,session,move,snap,imgpng,wall,gnomecompat,unitymtgrabhandles,animation,workarounds,expo,fade,ezoom,scale,unityshell]
CompositorRunning: compiz
DistUpgraded: Fresh install
DistroCodename: precise
DistroRelease: Ubuntu 12.04
DistroVariant: ubuntu
DkmsStatus: bcmwl, 5.100.82.38+bdcom, 3.2.0-8-generic, x86_64: installed
ExtraDebuggingInterest: Yes, whatever it takes to get this fixed in Ubuntu
GraphicsCard:
 Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Apple Computer Inc. Device [106b:00ea]
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64+mac (20120108)
MachineType: Apple Inc. MacBookAir4,1
NonfreeKernelModules: wl
Package: xserver-xorg-video-intel 2:2.15.901-1ubuntu4
PackageArchitecture: amd64
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-8-generic root=UUID=02e7076b-bab1-4657-ae2c-d6c733869f1c ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 3.2.0-8.15-generic 3.2.0
Tags: precise running-unity ubuntu single-occurrence reproducible compiz-0.9
Uname: Linux 3.2.0-8-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
dmi.bios.date: 10/14/2011
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBA41.88Z.0077.B0E.1110141154
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-C08A6BB70A942AC2
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookAir4,1
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-C08A6BB70A942AC2
dmi.modalias: dmi:bvnAppleInc.:bvrMBA41.88Z.0077.B0E.1110141154:bd10/14/2011:svnAppleInc.:pnMacBookAir4,1:pvr1.0:rvnAppleInc.:rnMac-C08A6BB70A942AC2:rvrMacBookAir4,1:cvnAppleInc.:ct10:cvrMac-C08A6BB70A942AC2:
dmi.product.name: MacBookAir4,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.
version.compiz: compiz 1:0.9.6+bzr20110929-0ubuntu8
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.30-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 7.11-0ubuntu4
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.11-0ubuntu4
version.xserver-xorg-core: xserver-xorg-core 2:1.10.4-1ubuntu6
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.6.0-1ubuntu13
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20110811.g93fc084-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.15.901-1ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20111201+b5534a1-1

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

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[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Li Li (lli5)]

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Update: installing the current mainline kernel (Linux li-MBA 3.2.0-8-generic #15-Ubuntu SMP Wed Jan 11 13:57:44 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux) didn't fix the issue.

[Li Li (lli5)]

Correct comment #45 above: the mainline kernel is "Linux version 3.2.0-999-generic (root@gomeisa) (gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5) ) #201201110439 SMP Wed Jan 11 09:40:53 UTC 2012"

[Bryce Harrington (bryce)]

Generally these types of issues should be analyzed as gnome-power-manager issues first, then driver issues if g-p-m can be ruled out.

It's possible g-p-m is simply not tracking your backlight settings correctly, or not updating them properly on reboot.

[Martin Pitt (pitti)]

Yes, the power plugin does not store the current brightness and restores it on startup.

[Martin Pitt (pitti)]

Reported upstream. I don't think that's something that we can spend time on very soon, so unassigning. We'll be happy to relay possible solutions/patches to upstream, of course.

[luk1don (luk1don)]

This:
pkexec /usr/lib/gnome-settings-daemon/gsd-backlight-helper --set-brightness 0

[inneas (inneas)]

Same problem here on a ThinkPad X230 running Ubuntu 13.04.
The brightness-setting isn't saved and goes to maximum on every reboot (annoying!) .

As a workaround i put

echo 10 > /sys/class/backlight/acpi_video0/brightness

into /etc/rc.local

This worked until the latest kernel update. Now the brightness is set to a lower level during boot, but it goes immediately back to the maximum.
(uname -a: 3.8.0-19-generic #30-Ubuntu SMP Wed May 1 16:36:13 UTC 2013 i686 i686 i686 GNU/Linux)

[Guillaume Michaud (gfmichaud)]

This has to do with ACPI.
I solved this problem on my Asus Zenbook UX31E (with latest BIOS) this way :

1) I added acpi_osi='!Windows 2012' acpi_backlight=vendor in /etc/default/default so that the line looks like
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi='!Windows 2012' acpi_backlight=vendor"

2) I ran sudo update-grub (to re-generate GRUB conf files)

To explain, I forced the kernel to say to the BIOS that Windows 8 is running on the laptop.
Maybe something similar should work on other PCs / Macbook.

It's a better way to fix this than a workaround such as adding a script to set backlight to a certain level.

[inneas (inneas)]

I have this already in my grub.cfg. Without this the Fn-keys for brightness aren't working.
( see https://bugs.launchpad.net/linux/+bug/1098216 )

But this doesn't fix the problem with maximum brightness on boot (at ThinkPad X230).

[Guillaume Michaud (gfmichaud)]

Have you tried setting the brightness using the "Britghtness & Lock" window, instead of using the "Fn" keys ?

On my Zenbook, the "Fn" keys work but their action is not saved ; on the opposite, the settings I choose "Britghtness & Lock" are saved and restored at boot.

[inneas (inneas)]

Yes, I tried both. Do you know where this setting should be stored?