kernel-packages team mailing list archive

[Joseph Salisbury <joseph.salisbury@xxxxxxxxxxxxx>]

Would it be possible for you to test the latest upstream kernel? Refer
to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest
v3.18 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/v3.18-rc3-vivid/

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

** Changed in: linux (Ubuntu)
       Status: Confirmed => Incomplete

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https://bugs.launchpad.net/bugs/1388817

Title:
  Backlight brightness problem with Thinkpad T440S

Status in “linux” package in Ubuntu:
  Incomplete

Bug description:
  At the beginning, I have the following four problems:

  1. After every boot, the brightness is set to maximum.
  2. The brightness can't be adjusted smoothly. Only 4 brightnesses can be achieved with Fn keys.
  3. After recovering from screen dimming and system suspend, the brightness is set to maximum.
  4. The following error message is printed during the boot:
  [ 12.843633] thinkpad_acpi: Unsupported brightness interface, please contact ibm-acpi-devel@xxxxxxxxxxxxxxxxxxxxx

  The following workaround fixes 1 for me.
  http://askubuntu.com/questions/151651/brightness-is-reset-to-maximum-on-every-restart

  I add "acpi_backlight=vendor" kernel parameter according to
  https://wiki.ubuntu.com/Kernel/Debugging/Backlight. This fixes 2 and 3
  for me.

  But 4 still exists.

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: linux-image-3.13.0-39-generic 3.13.0-39.66
  ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
  Uname: Linux 3.13.0-39-generic x86_64
  ApportVersion: 2.14.1-0ubuntu3.5
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  jing       2280 F.... pulseaudio
   /dev/snd/controlC1:  jing       2280 F.... pulseaudio
   /dev/snd/pcmC1D0p:   jing       2280 F...m pulseaudio
  CurrentDesktop: Unity
  Date: Mon Nov  3 20:51:08 2014
  HibernationDevice: RESUME=UUID=4bfed795-9c38-418e-b097-83b17523308e
  InstallationDate: Installed on 2014-06-28 (128 days ago)
  InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
  MachineType: LENOVO 20AQA02QHH
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-39-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash acpi_backlight=vendor vt.handoff=7
  RelatedPackageVersions:
   linux-restricted-modules-3.13.0-39-generic N/A
   linux-backports-modules-3.13.0-39-generic  N/A
   linux-firmware                             1.127.7
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 02/21/2014
  dmi.bios.vendor: LENOVO
  dmi.bios.version: GJET72WW (2.22 )
  dmi.board.asset.tag: Not Available
  dmi.board.name: 20AQA02QHH
  dmi.board.vendor: LENOVO
  dmi.board.version: 0B98405 STD
  dmi.chassis.asset.tag: No Asset Information
  dmi.chassis.type: 10
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: Not Available
  dmi.modalias: dmi:bvnLENOVO:bvrGJET72WW(2.22):bd02/21/2014:svnLENOVO:pn20AQA02QHH:pvrThinkPadT440s:rvnLENOVO:rn20AQA02QHH:rvr0B98405STD:cvnLENOVO:ct10:cvrNotAvailable:
  dmi.product.name: 20AQA02QHH
  dmi.product.version: ThinkPad T440s
  dmi.sys.vendor: LENOVO

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