[Lenovo ThinkPad X220] Undocking notebook results in minimum brightness

[Akif D.]

I've a X220 in 14.04 with a docking station connected to an external monitor. Undocking my notebook darkens the notebook screen.

WORKAROUND: Docking it again gives normal brightness and "undocking" again gives again regular brightness.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-36-generic 3.13.0-36.63
ProcVersionSignature: Ubuntu 3.13.0-36.63-generic 3.13.11.6
Uname: Linux 3.13.0-36-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: adnc 2737 F.... pulseaudio
 /dev/snd/pcmC0D0p: adnc 2737 F...m pulseaudio
CurrentDesktop: Unity
Date: Fri Oct 3 13:41:38 2014
HibernationDevice: RESUME=UUID=e24f10db-88ff-46e1-9e2c-15cb62ebb376
InstallationDate: Installed on 2014-07-02 (92 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
MachineType: LENOVO 4290C88
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-36-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-36-generic N/A
 linux-backports-modules-3.13.0-36-generic N/A
 linux-firmware 1.127.7
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/18/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: 8DET69WW (1.39 )
dmi.board.asset.tag: Not Available
dmi.board.name: 4290C88
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr8DET69WW(1.39):bd07/18/2013:svnLENOVO:pn4290C88:pvrThinkPadX220:rvnLENOVO:rn4290C88:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 4290C88
dmi.product.version: ThinkPad X220
dmi.sys.vendor: LENOVO

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.17 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

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.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.17-rc7-utopic/

[Akif D. (adadnc)]

I tested "Linux aknoteb 3.17.0-031700rc7-generic #201409281835 SMP Sun Sep 28 22:36:30 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux"

I've done several tests and they all show that the reported behaviour does not exists on the above kernel. Is this kernel going to be published for 14.04 and if yes when?

[penalvch (penalvch)]

Akif D., the next step is to fully reverse commit bisect the kernel in order to identify the offending commit. Could you please do this following https://wiki.ubuntu.com/Kernel/KernelBisection#How_do_I_reverse_bisect_the_upstream_kernel.3F ?

[Akif D. (adadnc)]

I found out that the faulty behaviour when undocking ist still present in:
  3.13.11-03131108-generic #201410031135 SMP Fri Oct 3 15:36:25 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

But working in:
   3.14.1-031401-generic #201404141220 SMP Mon Apr 14 16:21:48 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

[eliash (elia-shreidler)]

Hi guys, I'm experiencing this behaviour with kernel -
3.17.3-031703-generic

Lenovo x230

$ cat /etc/issue
Ubuntu 12.04.5 LTS \n \l

$ uname -a
Linux ****-ubuntu 3.17.3-031703-generic #201411141335 SMP Fri Nov 14 18:36:40 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

[eliash (elia-shreidler)]

In addition, need to mention that I experience the brightness going to minimum on:
* Undock
* after waking up from suspend

[Launchpad Janitor (janitor)]

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