Backlight keys not working on ASUS N550JK

[Jérôme Poulin]

Backlight keys are not working when logged in the desktop, using /sys/class/backlight/intel_backlight/brightness can adjust the brightness.

Usual workarounds listed in https://wiki.ubuntu.com/Kernel/Debugging/Backlight are not working.

WORKAROUND: Add to GRUB:
acpi_osi=

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.16.0-30-generic 3.16.0-30.40~14.04.1
ProcVersionSignature: Ubuntu 3.16.0-30.40~14.04.1-generic 3.16.7-ckt3
Uname: Linux 3.16.0-30-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.6
Architecture: amd64
CurrentDesktop: Unity
Date: Fri Feb 13 15:46:37 2015
SourcePackage: linux-lts-utopic
UpgradeStatus: Upgraded to trusty on 2014-03-25 (325 days ago)
---
ApportVersion: 2.17.2-0ubuntu1.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: jerome.poulin 3195 F.... pulseaudio
 /dev/snd/controlC1: jerome.poulin 3195 F.... pulseaudio
CurrentDesktop: Unity
DistroRelease: Ubuntu 15.04
MachineType: ASUSTeK COMPUTER INC. N550JK
Package: linux (not installed)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: root=/dev/vgUbuntu/root initrd=EFI/ubuntuefi/initrd splash quiet resume=/dev/mapper/vgUbuntu-swap acpi_osi=
ProcVersionSignature: Ubuntu 3.19.0-22.22-generic 3.19.8-ckt1
RelatedPackageVersions:
 linux-restricted-modules-3.19.0-22-generic N/A
 linux-backports-modules-3.19.0-22-generic N/A
 linux-firmware 1.143.2
Tags: vivid
Uname: Linux 3.19.0-22-generic x86_64
UpgradeStatus: Upgraded to vivid on 2015-06-12 (44 days ago)
UserGroups: adm dialout docker fuse kismet libvirtd lp messagebus mlocate plugdev pulse-access src sudo users vboxusers video wireshark
_MarkForUpload: True
dmi.bios.date: 09/26/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: N550JK.208
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: N550JK
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrN550JK.208:bd09/26/2014:svnASUSTeKCOMPUTERINC.:pnN550JK:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnN550JK:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:
dmi.product.name: N550JK
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[penalvch (penalvch)]

Jérôme Poulin, thank you for reporting this and helping make Ubuntu better. Could you please execute the following command, as it will automatically gather debugging information, in a terminal:
apport-collect 1421834

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Jérôme Poulin (jeromepoulin)]

It now works on Ubuntu Vivid only if «acpi_osi=» is added to GRUB.

[Jérôme Poulin (jeromepoulin)]

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[Jérôme Poulin (jeromepoulin)]

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[Jérôme Poulin (jeromepoulin)]

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[Jérôme Poulin (jeromepoulin)]

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[Jérôme Poulin (jeromepoulin)]

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[Jérôme Poulin (jeromepoulin)]

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[Jérôme Poulin (jeromepoulin)]

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[Jérôme Poulin (jeromepoulin)]

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[penalvch (penalvch)]

Jérôme Poulin, could you please test the latest upstream kernel available from the very top line at the top of the page (the release names are irrelevant for testing, and please do not test the daily folder) following https://wiki.ubuntu.com/Kernel/MainlineBuilds ? It will allow additional upstream developers to examine the issue.

If the test did not allow you to test to the issue (ex. you couldn't boot into the OS) please make a comment in your report about this, and continue to test the next most recent kernel version until you can test to 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 by clicking on the yellow circle with a black pencil icon, next to the word Tags, located at the bottom of the report description:
kernel-fixed-upstream
kernel-fixed-upstream-X.Y-rcZ

Where X, Y, and Z are numbers corresponding to the kernel version.

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-X.Y-rcZ

Please note, an error to install the kernel does not fit the criteria of kernel-bug-exists-upstream.

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

Thank you for your understanding.

[Jérôme Poulin (jeromepoulin)]

I am currently running 4.2-rc3, I tested with acpi_osi= and backlight control work, however, if I remove the workaround from GRUB command line on boot, backlight keys stop working.

[penalvch (penalvch)]

Jérôme Poulin, the issue you are reporting is an upstream one. Could you please report this problem to the appropriate mailing list (linux-acpi) by following the instructions verbatim at https://wiki.ubuntu.com/Bugs/Upstream/kernel ?

Please provide a direct URL to your e-mail to the mailing list once you have made it so that it may be tracked via http://vger.kernel.org/vger-lists.html . It can take a day for the new e-mail to show up in the respective archive.

Thank you for your understanding.

[penalvch (penalvch)]

Jérôme Poulin, could you please test the latest mainline kernel (4.2) and advise to the results?

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]