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[Björn Cassens <bjoern.cassens@xxxxxxxxxxxxxx>]

Hi, here are all files you wanted in a tar.gz file format. Every output
is marked, when the files have been generated (backlight_ok or
backlight_NOT_ok). One maybe important fact is, that if i write in to
/etc/classes/.../brightness nothing happens, the file actual_brightness
shows the written value. But if I'm using xcfe4-power-manager and using
the Fn keys it seems to be working and the value in the file
actual_brightness changes as well. When i reach the highes possible
brightness, the file actual_brightness does not show 100 (which is the
max brightness when i'm using the kernel, where the brightness control
seems to be working) instead of this it shows only the number 6. The
same behavior applies to the not working version of the kernel.

** Attachment added: "acpi-tables.txt"
   https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1243267/+attachment/3887574/+files/acpi-tables.txt

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https://bugs.launchpad.net/bugs/1243267

Title:
  Backlight brightness control doesn't work

Status in “linux” package in Ubuntu:
  Confirmed

Bug description:
  Hello, during a kernel update from 3.11.0-4 up to 3.11.0-9 i've found out that my brightness controll of my Notebook (Lenovo Thinkpad T430-D17 (nvidia-graphic card, optimus disabled, driver version: 325.15) does not work). Therefore, i have tried several kernel from kernel.org where all Kernel provides the backlight control. To get comparable values, i have tried the kernel version 
  ubuntu-kernel: Ubuntu 3.12.0-0.2-generic and 3.12.0-rc6
  By using the the ubuntu kernel, i wasn't able to control the backlight brightness but by using the kernel profided by kernel.org works. Therefore, i began to search the patch lists of ubuntu and find this patch: http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-trusty.git;a=blobdiff;f=drivers/acpi/blacklist.c;h=f49ffaedaefdaa28d533d339a3f5cda073687ed7;hp=9515f18898b2b578053c58309185daa7934cfdda;hb=02cb06962306d96f59bc97ec8289c14b73bafb4e;hpb=2eb9acd1a1deb3f4d6428d022fc43541c9e70069.
  I have reverted this patch and the brightness control of my notebook works fine. 

  If anybody wants to execute the ubuntu-bug program, you should note,
  that i'm not using ubuntu, i'm only using the ubuntu kernel and the
  ubuntu-bug program is not in my repositories. Therefore, i supply the
  lspci-vnvn report. If any other logs or reports are missing please
  feel free to ask me.

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