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[Brad Figg <brad.figg@xxxxxxxxxxxxx>]

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

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https://bugs.launchpad.net/bugs/1320412

Title:
  [Lenovo IdeaPad y510p] Brightness settings do not affect the actual
  display brightness

Status in “linux” package in Ubuntu:
  Confirmed

Bug description:
  When I press Fn+Up/Down on my keyboard (the brightness adjust hotkey),
  the brightness settings the slider moves, however the actual
  brightness of my laptop display remains the same.

  As per https://wiki.ubuntu.com/Kernel/Debugging/Backlight, I have
  attached the output of several commands as debugging information.

  Using the kernel parameter acpi_backlight=vendor, I can no longer
  adjust the brightness slider with my keyboard hotkey Fn+Up/Down Arrow,
  and when I go to System Settings -> Brightness & Lock, the brightness
  slider is no longer present.

  The kernel paramater video.use_bios_initial_backlight=0 appears to
  make no difference, as I can move the brightness slider and it still
  has no effect.

  The kernel paramater video.use_native_backlight=1 also has no
  noticeable effect.

  When booting with the latest mainline kernel (v3.15-rc5-utopic), the
  issue persists.

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: linux-image-3.13.0-24-generic 3.13.0-24.47
  ProcVersionSignature: Ubuntu 3.13.0-24.47-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:  travis     1559 F.... pulseaudio
   /dev/snd/controlC0:  travis     1559 F.... pulseaudio
  CurrentDesktop: Unity
  Date: Fri May 16 17:55:54 2014
  HibernationDevice: RESUME=UUID=85b9a9be-afa0-404e-8b11-c98f93fa4366
  InstallationDate: Installed on 2014-05-14 (2 days ago)
  InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
  MachineType: LENOVO 20217
  ProcEnviron:
   LANGUAGE=en_US
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  ProcFB: 0 EFI VGA
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-24-generic.efi.signed root=UUID=108a3bcd-f7e8-46e6-b5b8-1c1c0fb22903 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                             1.127.2
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 09/18/2013
  dmi.bios.vendor: LENOVO
  dmi.bios.version: 74CN44WW(V3.05)
  dmi.board.asset.tag: No Asset Tag
  dmi.board.name: VIQY0Y1
  dmi.board.vendor: LENOVO
  dmi.board.version: 31900058STD
  dmi.chassis.asset.tag: No Asset Tag
  dmi.chassis.type: 10
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: Lenovo IdeaPad Y510P
  dmi.modalias: dmi:bvnLENOVO:bvr74CN44WW(V3.05):bd09/18/2013:svnLENOVO:pn20217:pvrLenovoIdeaPadY510P:rvnLENOVO:rnVIQY0Y1:rvr31900058STD:cvnLENOVO:ct10:cvrLenovoIdeaPadY510P:
  dmi.product.name: 20217
  dmi.product.version: Lenovo IdeaPad Y510P
  dmi.sys.vendor: LENOVO

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