kernel-packages team mailing list archive

[Lewis Toohey <lewis@xxxxxxxxxxxx>]

No "fix" yet as such, however, thanks to kernel developer AAron Lu I can
confirm that there is a workaround to manually adjust screen brightness.

Its not overly practical, but you possibly write a script to do it. The
sequence of commands is below. Essentially it involves accessing your
video card via /sys and poking the brightness value directly. Mine video
is detected as radeon_bl0.

I will revert when I have further information.


lewis@HappyFunMeaowMeaow:~$ sudo -s
[sudo] password for lewis: 
root@HappyFunMeaowMeaow:~# cd /sys/class/backlight/radeon_bl0
root@HappyFunMeaowMeaow:/sys/class/backlight/radeon_bl0# cat max_brightness 
255 #Max value for your hardware
root@HappyFunMeaowMeaow:/sys/class/backlight/radeon_bl0# echo 200 > brightness #Example
root@HappyFunMeaowMeaow:/sys/class/backlight/radeon_bl0# echo 10 > brightness #Example
root@HappyFunMeaowMeaow:/sys/class/backlight/radeon_bl0# echo 255 > brightness #Example
root@HappyFunMeaowMeaow:/sys/class/backlight/radeon_bl0#

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You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1315834

Title:
  1002:983d [Acer Aspire V5-122P] Unable to adjust screen brightness

Status in “linux” package in Ubuntu:
  Triaged

Bug description:
  I am unable to adjust the screen brightness on my Acer Aspire V5-122P.
  Adjusting brightness in the settings applet has no affect. Adjusting
  brightness with the keyboard function keys turns the screen on and off
  seemingly randomly.

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: linux-image-3.13.0-24-generic 3.13.0-24.46
  ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9
  Uname: Linux 3.13.0-24-generic x86_64
  ApportVersion: 2.14.1-0ubuntu3
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC1:  lewis      2240 F.... pulseaudio
   /dev/snd/controlC0:  lewis      2240 F.... pulseaudio
  CurrentDesktop: Unity
  Date: Sun May  4 10:55:50 2014
  HibernationDevice: RESUME=UUID=42931b07-a2e1-49a1-9780-874e1d4300b7
  InstallationDate: Installed on 2014-04-14 (19 days ago)
  InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Beta amd64 (20140326)
  MachineType: Acer Aspire V5-122P
  ProcFB: 0 radeondrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-24-generic.efi.signed root=UUID=8a594eb2-ccc3-4aa4-a4c5-e872f4033b04 ro quiet splash vt.handoff=7
  RelatedPackageVersions:
   linux-restricted-modules-3.13.0-24-generic N/A
   linux-backports-modules-3.13.0-24-generic  N/A
   linux-firmware                             1.127
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 07/18/2013
  dmi.bios.vendor: Insyde Corp.
  dmi.bios.version: V2.08
  dmi.board.asset.tag: Base Board Asset Tag
  dmi.board.name: Aspire V5-122P
  dmi.board.vendor: Acer
  dmi.board.version: V2.08
  dmi.chassis.type: 10
  dmi.chassis.vendor: Acer
  dmi.chassis.version: V2.08
  dmi.modalias: dmi:bvnInsydeCorp.:bvrV2.08:bd07/18/2013:svnAcer:pnAspireV5-122P:pvrV2.08:rvnAcer:rnAspireV5-122P:rvrV2.08:cvnAcer:ct10:cvrV2.08:
  dmi.product.name: Aspire V5-122P
  dmi.product.version: V2.08
  dmi.sys.vendor: Acer

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