Setting brightness doesn't work out of the box on Acer Extensa 5235

[Bence Lukács]

I use this laptop since 10.04 and I always have to write something into /etc/default/grub, to solve this problem.

WORKAROUND: Use kernel parameter:
acpi_backlight=vendor

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-3.2.0-17-generic-pae 3.2.0-17.27
ProcVersionSignature: Ubuntu 3.2.0-17.27-generic-pae 3.2.6
Uname: Linux 3.2.0-17-generic-pae i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.93-0ubuntu2
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: CONEXANT Analog [CONEXANT Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: lukibeni 1665 F.... pulseaudio
 /dev/snd/pcmC0D0p: lukibeni 1665 F...m pulseaudio
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf0700000 irq 45'
   Mixer name : 'Conexant CX20561 (Hermosa)'
   Components : 'HDA:14f15051,10250253,00100000'
   Controls : 18
   Simple ctrls : 12
Date: Sun Feb 26 09:19:11 2012
HibernationDevice: RESUME=UUID=9e4f77a4-98e9-48ec-97e5-07dc5ae08872
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha i386 (20120201.1)
MachineType: Acer Extensa 5235
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=hu_HU.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-17-generic-pae root=UUID=5b2cd82c-58ab-45e6-9719-02f98b6c857b ro quiet splash acpi_backlight=vendor vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-17-generic-pae N/A
 linux-backports-modules-3.2.0-17-generic-pae N/A
 linux-firmware 1.71
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/09/2009
dmi.bios.vendor: Phoenix
dmi.bios.version: V0.3216
dmi.board.name: BA50-MV
dmi.board.vendor: Acer
dmi.board.version: Not Applicable
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenix:bvrV0.3216:bd06/09/2009:svnAcer:pnExtensa5235:pvrNotApplicable:rvnAcer:rnBA50-MV:rvrNotApplicable:cvnAcer:ct10:cvrN/A:
dmi.product.name: Extensa 5235
dmi.product.version: Not Applicable
dmi.sys.vendor: Acer

[Joseph Salisbury (jsalisbury)]

Just to confirm, this bug is fixed in Precise, but you would like to see if the fix can be backported to previous releases?

[Bence Lukács (lukacs-bence1)]

For me brightness doesn't change in Precise, unless I write "acpi_backlight=vendor" to grub.
I don't mind the previous releases, I would be happy if it worked on Precise...

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.3 kernel[1] (Not a kernel in the daily directory). Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag(Only that one tag, please leave the other tags). This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text.

If this bug is fixed by the mainline kernel, please add the following tag 'kernel-fixed-upstream-KERNEL-VERSION'. For example, if kernel version 3.3-rc5 fixed the issue, the tag would be: 'kernel-fixed-upstream-v3.3-rc5'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[1] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.3-rc5-precise/

[Bence Lukács (lukacs-bence1)]

Theres only amd64 in 3.3-rc5. I can't install it because dpkg said it's not my architecture.
I use i368.

[Joseph Salisbury (jsalisbury)]

Thanks for the update, Bence. Can you test v3.3-rc4 then? It is available from:

http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.3-rc4-precise/

[Bence Lukács (lukacs-bence1)]

I've tested it, but the bug still exist in the upstream kernel.
If I write "acpi_backlight=vendor" into grub it works again.

[Joseph Salisbury (jsalisbury)]

This issue appears to be an upstream bug, since you tested the latest upstream kernel. Would it be possible for you to open an upstream bug report at bugzilla.kernel.org [1]? That will allow the upstream Developers to examine the issue, and may provide a quicker resolution to the bug.

If you are comfortable with opening a bug upstream, It would be great if you can report back the upstream bug number in this bug report. That will allow us to link this bug to the upstream report.

[1] https://wiki.ubuntu.com/Bugs/Upstream/kernel

[Bence Lukács (lukacs-bence1)]

I send a bug report to bugzilla.kernel.org
https://bugzilla.kernel.org/show_bug.cgi?id=42833

[penalvch (penalvch)]

Bence Lukács, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, could you please run the following command in the development release from a Terminal (Applications->Accessories->Terminal), as it will automatically gather and attach updated debug information to this report:

apport-collect -p linux <replace-with-bug-number>

Also, could you please test the latest upstream kernel available (not the daily folder, but the one all the way at the bottom) following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags:
kernel-fixed-upstream
kernel-fixed-upstream-VERSION-NUMBER

where VERSION-NUMBER is the version number of the kernel you tested. For example:
kernel-fixed-upstream-v3.12

This can be done by clicking on the yellow circle with a black pencil icon next to the word Tags located at the bottom of the bug description. As well, please remove the tag:
needs-upstream-testing

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-VERSION-NUMBER

As well, please remove the tag:
needs-upstream-testing

Once testing of the upstream kernel is complete, please mark this bug's Status as Confirmed. Please let us know your results. Thank you for your understanding.