kernel-packages team mailing list archive

[Joseph Salisbury <joseph.salisbury@xxxxxxxxxxxxx>]

Did this issue just start happening after a recent upgrade or update?
If so, we can perform a bisect to identify the commit that introduced
this bug.

Also, would it be possible for you to test the latest mainline kernel which is 3.14-rc1?  It can be downloaded from:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.14-rc1-trusty/

** Changed in: linux (Ubuntu)
   Importance: Undecided => Medium

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https://bugs.launchpad.net/bugs/1276037

Title:
  [Thinkpad T420s] Brightness dims when unplugging external monitor and
  cannot be changed afterwards

Status in “linux” package in Ubuntu:
  Confirmed

Bug description:
  Steps to reproduce

  1) Plug a T420s to an external monitor using Displayport
  2) Both external and internal monitor  look right
  3) Unplug (via software or hardware) the external monitor

  Expected results:
  The brightness in the internal monitor stays the same and it can be changed through system keys or system settings

  Actual results:
  The brightness in the internal monitor  dims and it cannot be changed until the system is rebooted

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: linux-image-3.13.0-6-generic 3.13.0-6.23
  ProcVersionSignature: Ubuntu 3.13.0-6.23-generic 3.13.0
  Uname: Linux 3.13.0-6-generic x86_64
  ApportVersion: 2.13.2-0ubuntu2
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  ara        2409 F.... pulseaudio
  CurrentDesktop: Unity
  Date: Tue Feb  4 09:06:02 2014
  HibernationDevice: RESUME=UUID=85ebfa4c-a925-4edf-9764-79ecfaa29ae6
  InstallationDate: Installed on 2013-06-17 (231 days ago)
  InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
  MachineType: LENOVO 4171CTO
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-6-generic root=UUID=35693a74-fe03-4399-920c-24bfaf0a5649 ro quiet splash vt.handoff=7
  RelatedPackageVersions:
   linux-restricted-modules-3.13.0-6-generic N/A
   linux-backports-modules-3.13.0-6-generic  N/A
   linux-firmware                            1.123
  SourcePackage: linux
  UpgradeStatus: Upgraded to trusty on 2014-01-20 (14 days ago)
  dmi.bios.date: 07/11/2012
  dmi.bios.vendor: LENOVO
  dmi.bios.version: 8CET54WW (1.34 )
  dmi.board.asset.tag: Not Available
  dmi.board.name: 4171CTO
  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:bvr8CET54WW(1.34):bd07/11/2012:svnLENOVO:pn4171CTO:pvrThinkPadT420s:rvnLENOVO:rn4171CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
  dmi.product.name: 4171CTO
  dmi.product.version: ThinkPad T420s
  dmi.sys.vendor: LENOVO

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