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[Launchpad Bug Tracker <1258495@xxxxxxxxxxxxxxxxxx>]

[Expired for linux (Ubuntu) because there has been no activity for 60
days.]

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

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https://bugs.launchpad.net/bugs/1258495

Title:
  8086:27ae [Acer AOA110] backlight too bright, can't dim it much

Status in “linux” package in Ubuntu:
  Expired

Bug description:
  Screen is far too bright, dims only slightly with hotkeys, brightness
  control applet ineffective. Tried more than half a dozen solutions
  (incl. editing the grub which used to work fine with Ubuntu 12.04) but
  none of them worked.

  thindi@thindi-AOA110:~$ ls /sys/class/backlight > backlight
  thindi@thindi-AOA110:~$ grep -r . /proc/acpi > acpi
  grep: /proc/acpi/event: Permission denied
  thindi@thindi-AOA110:~$ sudo acpidump -o acpidump.txt
  thindi@thindi-AOA110:~$ acpixtract acpidump.txt
  Acpi table [DSDT] -  24038 bytes written to DSDT.dat
  Acpi table [SSDT] -   1220 bytes written to SSDT.dat
  thindi@thindi-AOA110:~$ iasl -d DSDT.dat

  Intel ACPI Component Architecture
  AML Disassembler version 20100528 [Dec 19 2012]
  Copyright (c) 2000 - 2010 Intel Corporation
  Supports ACPI Specification Revision 4.0a

  Loading Acpi table from file DSDT.dat
  Acpi table [DSDT] successfully installed and loaded
  Pass 1 parse of [DSDT]
  Pass 2 parse of [DSDT]
  Parsing Deferred Opcodes (Methods/Buffers/Packages/Regions)
  ...................................................................................................................................................................................................................................................................................................................................................................
  Parsing completed
  Disassembly completed, written to "DSDT.dsl"
  sudo fwts > fwts
  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1258495/+attachment/3931116/+files/fwts

  thindi@thindi-AOA110:~$ dmesg | grep 'ACPI: Video' > video
  thindi@thindi-AOA110:~$ sudo dmidecode > dmidecode.log
  thindi@thindi-AOA110:~$ cat /proc/version > version

  Reboot with only the kernel parameter acpi_backlight=vendor:
  If that means the grub file (excerpt)  should look like this:
  GRUB_DEFAULT=0
  GRUB_HIDDEN_TIMEOUT=0
  GRUB_HIDDEN_TIMEOUT_QUIET=true
  GRUB_TIMEOUT=10
  GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
  GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor"
  GRUB_CMDLINE_LINUX=""

  Make a comment on if you can now alter the backlight with hotkeys or a brightness applet.
  Neither do the job.

  thindi@thindi-AOA110:~$ ls /sys/class/backlight > vendorbacklight
  thindi@thindi-AOA110:~$ sudo su
  root@thindi-AOA110:/home/thindi# ls -la /sys/class/backlight/intel_backlight/ > lslabacklight
  root@thindi-AOA110:/home/thindi# echo 8 > /sys/class/backlight/intel_backlight/brightness
  No change after doing that.

  o "Reboot with kernel parameter video.use_bios_initial_backlight=0"

  Don't know how to do that.

  Dealing with the rest on this site
  https://wiki.ubuntu.com/Kernel/Debugging/Backlight is out of my depth.

  ProblemType: Bug
  DistroRelease: Ubuntu 13.10
  Package: linux-image-3.11.0-14-generic 3.11.0-14.21
  ProcVersionSignature: Ubuntu 3.11.0-14.21-generic 3.11.7
  Uname: Linux 3.11.0-14-generic i686
  ApportVersion: 2.12.5-0ubuntu2.1
  Architecture: i386
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  thindi     1586 F.... pulseaudio
   /dev/snd/pcmC0D0p:   thindi     1586 F...m pulseaudio
  Date: Fri Dec  6 11:31:38 2013
  HibernationDevice: RESUME=UUID=9793476b-8516-4e8d-b628-0dd0389b1376
  InstallationDate: Installed on 2013-12-03 (3 days ago)
  InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release i386 (20131016.1)
  MachineType: Acer AOA110
  MarkForUpload: True
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-14-generic root=UUID=bf6adaec-4e58-4748-95d7-8d287f559046 ro quiet splash pcie_aspm=force acpi_backlight=vendor vt.handoff=7
  RelatedPackageVersions:
   linux-restricted-modules-3.11.0-14-generic N/A
   linux-backports-modules-3.11.0-14-generic  N/A
   linux-firmware                             1.116
  RfKill:
   0: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: no
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 10/06/2008
  dmi.bios.vendor: Acer
  dmi.bios.version: v0.3309
  dmi.board.asset.tag: Base Board Asset Tag
  dmi.board.vendor: Acer
  dmi.board.version: Base Board Version
  dmi.chassis.type: 1
  dmi.chassis.vendor: Chassis Manufacturer
  dmi.chassis.version: Chassis Version
  dmi.modalias: dmi:bvnAcer:bvrv0.3309:bd10/06/2008:svnAcer:pnAOA110:pvr1:rvnAcer:rn:rvrBaseBoardVersion:cvnChassisManufacturer:ct1:cvrChassisVersion:
  dmi.product.name: AOA110
  dmi.product.version: 1
  dmi.sys.vendor: Acer

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