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[Bug 1402365] Re: Backlight Bug


I have downloaded Ubuntu 15.04 64 Bit ISO and running live session. It
is working on kernel 3.19.0-15 on Ubuntu 15.04.

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  Backlight Bug

Status in linux package in Ubuntu:

Bug description:
  Backlight control does not work, but there are entries in

  ls /sys/class/backlight > backlight
  grep -r . /proc/acpi > acpi
  sudo acpidump -o acpidump.txt
  acpixtract acpidump.txt
  iasl -d DSDT.dat
  sudo fwts > fwts
  sudo fwts method > fwts_method
  dmesg | grep 'ACPI: Video' > video
  sudo dmidecode > dmidecode.log
  cat /proc/version > version

  Testing for a work around
  Reboot with only the kernel parameter acpi_backlight=vendor
  does not work
  ls /sys/class/backlight > vendorbacklight

  No such folder /sys/class/backlight/intel_backlight/

  Reboot with just kernel parameter video.use_bios_initial_backlight=0
  does not work

  reboot with just kernel parameter video.use_native_backlight=1
  does not work

  WORKAROUND: Install fglrx.

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: linux-image-3.13.0-43-generic 3.13.0-43.72
  ProcVersionSignature: Ubuntu 3.13.0-43.72-generic
  Uname: Linux 3.13.0-43-generic x86_64
  ApportVersion: 2.14.1-0ubuntu3.6
  Architecture: amd64
   /dev/snd/controlC1:  vidya      1832 F.... pulseaudio
   /dev/snd/controlC0:  vidya      1832 F.... pulseaudio
  CurrentDesktop: Unity
  Date: Sun Dec 14 16:16:27 2014
  HibernationDevice: RESUME=UUID=42b35770-926b-43cf-8874-b5452e26b5e5
  InstallationDate: Installed on 2014-12-13 (0 days ago)
  InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
  MachineType: LENOVO 80E3
  ProcFB: 0 EFI VGA
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-43-generic.efi.signed root=UUID=7eccd389-f558-421b-928a-541b3f1c16f0 ro quiet splash vt.handoff=7 video.use_native_backlight=1
   linux-restricted-modules-3.13.0-43-generic N/A
   linux-backports-modules-3.13.0-43-generic  N/A
   linux-firmware                             1.127.10
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 08/26/2014
  dmi.bios.vendor: LENOVO
  dmi.bios.version: A2CN25WW(V1.07)
  dmi.board.asset.tag: No Asset Tag
  dmi.board.name: Lancer 5B2
  dmi.board.vendor: LENOVO
  dmi.board.version: SDK0F82990 WIN
  dmi.chassis.asset.tag: No Asset Tag
  dmi.chassis.type: 10
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: Lenovo G50-45
  dmi.modalias: dmi:bvnLENOVO:bvrA2CN25WW(V1.07):bd08/26/2014:svnLENOVO:pn80E3:pvrLenovoG50-45:rvnLENOVO:rnLancer5B2:rvrSDK0F82990WIN:cvnLENOVO:ct10:cvrLenovoG50-45:
  dmi.product.name: 80E3
  dmi.product.version: Lenovo G50-45
  dmi.sys.vendor: LENOVO

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