kernel-packages team mailing list archive

[Jingguo Yao <1388817@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

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 dimming, 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

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: Confirmed


** Tags: amd64 apport-bug trusty

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

Title:
  Backlight brightness problem with Thinkpad T440S

Status in “linux” package in Ubuntu:
  Confirmed

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 dimming, 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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