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Thread
Date
[Bug 1389215] Re: Brightness controls are not working in Unity / Xorg because of Nvidia proprietary driver.

To: desktop-packages@xxxxxxxxxxxxxxxxxxx
From: "Christopher M. Penalver" <christopher.m.penalver@xxxxxxxxx>
Date: Thu, 26 Feb 2015 00:06:13 -0000
Reply-to: Bug 1389215 <1389215@xxxxxxxxxxxxxxxxxx>
Sender: bounces@xxxxxxxxxxxxx
** Tags added: needs-vivid-test

** Changed in: xorg (Ubuntu)
   Importance: Undecided => Low

** Changed in: xorg (Ubuntu)
       Status: New => Incomplete

** Description changed:

  Brightness controls are not working in Unity / Xorg.  When pressing the
  keys <fn><home> and <fn><end> on my Lenovo W510, I see the indicator on
  the screen showing the level of brightness changing, so key mapping is
  not the problem.  However, the brightness is not changing.
  
  On the kernel level, I have the single following device:
  
  # cd /sys/class/backlight
  # ls -l
  total 0
  lrwxrwxrwx 1 root root 0 Nov  3 17:16 acpi_video0 -> ../../devices/pci0000:00/0000:00:03.0/0000:01:00.0/backlight/acpi_video0
  
  When playing with the <fn><home> and <fn><end>, the value of
  /sys/class/backlight/brightness changes accordingly.  The screen
  brightness does not change.
  
  Performing:
  
  # echo 10 >brightness
  
  ...does not have any effect (regardless of the value provided, 10 being
  just an example).
  
  WORKAROUND
  
  There is an odd workaround.  Simply go to the console using
  <CTRL><ALT><F1> and using the <fn><home> and <fn><end> keys, brightness
  then changes.  Return to Unity / Xorg with <CTRL><ALT><F7> and the
  selected brightness persists.
  
  NON WORKING WORKAROUND
  
  On the web, I read that adding:
  
  Option "RegistryDwords" "EnableBrightnessControl=1"'
  
  in xorg.conf might fix the problem.  I do not have an xorg and when I
  let the proprietary Nvidia driver generate one and add this option, X
  does not start anymore.
  
  Ubuntu 14.04.1 LTS with latest updates as of this writing.
  
  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: xorg 1:7.7+1ubuntu8
  ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
  Uname: Linux 3.13.0-39-generic x86_64
  NonfreeKernelModules: nvidia
  .proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0'
  .proc.driver.nvidia.registry: Binary: ""
  .proc.driver.nvidia.version:
-  NVRM version: NVIDIA UNIX x86_64 Kernel Module  331.38  Wed Jan  8 19:32:30 PST 2014
-  GCC version:  gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
+  NVRM version: NVIDIA UNIX x86_64 Kernel Module  331.38  Wed Jan  8 19:32:30 PST 2014
+  GCC version:  gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
  .tmp.unity.support.test.0:
-  
+ 
  ApportVersion: 2.14.1-0ubuntu3.5
  Architecture: amd64
  CompizPlugins: [core,bailer,detection,composite,opengl,compiztoolbox,decor,place,put,snap,resize,move,regex,session,vpswitch,imgpng,gnomecompat,text,ring,grid,mousepoll,animation,unitymtgrabhandles,wall,expo,ezoom,workarounds,fade,scale,unityshell]
  CompositorRunning: compiz
  CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
  CompositorUnredirectFSW: true
  CurrentDesktop: Unity
  Date: Tue Nov  4 07:38:59 2014
  DistUpgraded: Fresh install
  DistroCodename: trusty
  DistroVariant: ubuntu
  DkmsStatus:
-  bbswitch, 0.7, 3.13.0-32-generic, x86_64: installed
-  bbswitch, 0.7, 3.13.0-39-generic, x86_64: installed
-  nvidia-331, 331.38, 3.13.0-32-generic, x86_64: installed
-  nvidia-331, 331.38, 3.13.0-39-generic, x86_64: installed
-  tp-smapi, 0.41, 3.13.0-32-generic, x86_64: installed
+  bbswitch, 0.7, 3.13.0-32-generic, x86_64: installed
+  bbswitch, 0.7, 3.13.0-39-generic, x86_64: installed
+  nvidia-331, 331.38, 3.13.0-32-generic, x86_64: installed
+  nvidia-331, 331.38, 3.13.0-39-generic, x86_64: installed
+  tp-smapi, 0.41, 3.13.0-32-generic, x86_64: installed
  ExtraDebuggingInterest: Yes
  GraphicsCard:
-  NVIDIA Corporation GT216GLM [Quadro FX 880M] [10de:0a3c] (rev a2) (prog-if 00 [VGA controller])
-    Subsystem: Lenovo Device [17aa:2145]
+  NVIDIA Corporation GT216GLM [Quadro FX 880M] [10de:0a3c] (rev a2) (prog-if 00 [VGA controller])
+    Subsystem: Lenovo Device [17aa:2145]
  InstallationDate: Installed on 2014-11-01 (3 days ago)
  InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
  MachineType: LENOVO 4318CTO
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-39-generic root=UUID=994f9c2c-f967-472e-ace3-23cd620ec702 ro quiet splash
  SourcePackage: xorg
  Symptom: display
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 10/03/2012
  dmi.bios.vendor: LENOVO
  dmi.bios.version: 6NET84WW (1.45 )
  dmi.board.name: 4318CTO
  dmi.board.vendor: LENOVO
  dmi.board.version: Not Available
  dmi.chassis.asset.tag: No Asset Information
  dmi.chassis.type: 10
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: Not Available
  dmi.modalias: dmi:bvnLENOVO:bvr6NET84WW(1.45):bd10/03/2012:svnLENOVO:pn4318CTO:pvrThinkPadW510:rvnLENOVO:rn4318CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
  dmi.product.name: 4318CTO
  dmi.product.version: ThinkPad W510
  dmi.sys.vendor: LENOVO
  version.compiz: compiz 1:0.9.11.2+14.04.20140714-0ubuntu1
  version.ia32-libs: ia32-libs N/A
  version.libdrm2: libdrm2 2.4.52-1
  version.libgl1-mesa-dri: libgl1-mesa-dri 10.1.3-0ubuntu0.1
  version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
  version.libgl1-mesa-glx: libgl1-mesa-glx 10.1.3-0ubuntu0.1
  version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
  version.xserver-xorg-core: xserver-xorg-core 2:1.15.1-0ubuntu2.1
  version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.8.2-1ubuntu2
  version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.3.0-1ubuntu3.1
  version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.910-0ubuntu1.1
  version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.10-1ubuntu2
  xserver.bootTime: Tue Nov  4 01:40:35 2014
  xserver.configfile: default
  xserver.errors: open /dev/fb0: No such file or directory
  xserver.logfile: /var/log/Xorg.0.log
  xserver.outputs:
-  
+ 
  xserver.version: 2:1.15.1-0ubuntu2.1
- --- 
- .proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: u'/proc/driver/nvidia/gpus/0'
- .proc.driver.nvidia.registry: Binary: ""
- .proc.driver.nvidia.version:
-  NVRM version: NVIDIA UNIX x86_64 Kernel Module  331.113  Mon Dec  1 21:08:13 PST 2014
-  GCC version:  gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
- .tmp.unity.support.test.0:
-  
- ApportVersion: 2.14.1-0ubuntu3.7
- Architecture: amd64
- CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
- CompositorRunning: compiz
- CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
- CompositorUnredirectFSW: true
- CurrentDesktop: Unity
- DistUpgraded: Fresh install
- DistroCodename: trusty
- DistroRelease: Ubuntu 14.04
- DistroVariant: ubuntu
- ExtraDebuggingInterest: Yes
- GraphicsCard:
-  NVIDIA Corporation GT216GLM [Quadro FX 880M] [10de:0a3c] (rev a2) (prog-if 00 [VGA controller])
-    Subsystem: Lenovo Device [17aa:2145]
- InstallationDate: Installed on 2014-11-01 (116 days ago)
- InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
- MachineType: LENOVO 4318CTO
- NonfreeKernelModules: nvidia
- Package: xorg 1:7.7+1ubuntu8.1
- PackageArchitecture: amd64
- ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-46-generic root=UUID=994f9c2c-f967-472e-ace3-23cd620ec702 ro quiet splash
- ProcVersionSignature: Ubuntu 3.13.0-46.75-generic 3.13.11-ckt15
- Tags:  trusty possible-manual-nvidia-install ubuntu compiz-0.9
- Uname: Linux 3.13.0-46-generic x86_64
- UpgradeStatus: No upgrade log present (probably fresh install)
- UserGroups: adm admin audio cdrom dip floppy libvirtd lpadmin plugdev sambashare sambashare tape video www-data
- _MarkForUpload: True
- dmi.bios.date: 10/03/2012
- dmi.bios.vendor: LENOVO
- dmi.bios.version: 6NET84WW (1.45 )
- dmi.board.name: 4318CTO
- dmi.board.vendor: LENOVO
- dmi.board.version: Not Available
- dmi.chassis.asset.tag: No Asset Information
- dmi.chassis.type: 10
- dmi.chassis.vendor: LENOVO
- dmi.chassis.version: Not Available
- dmi.modalias: dmi:bvnLENOVO:bvr6NET84WW(1.45):bd10/03/2012:svnLENOVO:pn4318CTO:pvrThinkPadW510:rvnLENOVO:rn4318CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
- dmi.product.name: 4318CTO
- dmi.product.version: ThinkPad W510
- dmi.sys.vendor: LENOVO
- version.compiz: compiz 1:0.9.11.3+14.04.20150122-0ubuntu1
- version.ia32-libs: ia32-libs N/A
- version.libdrm2: libdrm2 2.4.56-1~ubuntu2
- version.libgl1-mesa-dri: libgl1-mesa-dri 10.1.3-0ubuntu0.3
- version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
- version.libgl1-mesa-glx: libgl1-mesa-glx 10.1.3-0ubuntu0.3
- version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
- version.xserver-xorg-core: xserver-xorg-core 2:1.15.1-0ubuntu2.7
- version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.8.2-1ubuntu2
- version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.3.0-1ubuntu3.1
- version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.910-0ubuntu1.4
- version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.10-1ubuntu2
- xserver.bootTime: Wed Feb 25 03:42:14 2015
- xserver.configfile: default
- xserver.errors: open /dev/fb0: No such file or directory
- xserver.logfile: /var/log/Xorg.0.log
- xserver.outputs:
-  
- xserver.version: 2:1.15.1-0ubuntu2.7

** Attachment removed: "xserver.devices.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327220/+files/xserver.devices.txt

** Attachment removed: "xdpyinfo.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327219/+files/xdpyinfo.txt

** Attachment removed: "nvidia-settings.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327218/+files/nvidia-settings.txt

** Attachment removed: "nvidia-installer.log.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327217/+files/nvidia-installer.log.txt

** Attachment removed: "Xrandr.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327216/+files/Xrandr.txt

** Attachment removed: "XorgLogOld.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327215/+files/XorgLogOld.txt

** Attachment removed: "XorgLog.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327214/+files/XorgLog.txt

** Attachment removed: "UnitySupportTest.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327213/+files/UnitySupportTest.txt

** Attachment removed: "UdevLog.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327212/+files/UdevLog.txt

** Attachment removed: "UdevDb.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327211/+files/UdevDb.txt

** Attachment removed: "ProcModules.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327210/+files/ProcModules.txt

** Attachment removed: "ProcInterrupts.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327209/+files/ProcInterrupts.txt

** Attachment removed: "ProcEnviron.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327208/+files/ProcEnviron.txt

** Attachment removed: "ProcCpuinfo.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327207/+files/ProcCpuinfo.txt

** Attachment removed: "NvidiaBugReportLog.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327206/+files/NvidiaBugReportLog.txt

** Attachment removed: "Lsusb.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327205/+files/Lsusb.txt

** Attachment removed: "Lspci.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327204/+files/Lspci.txt

** Attachment removed: "LightdmLog.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327203/+files/LightdmLog.txt

** Attachment removed: "LightdmGreeterLogOld.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327202/+files/LightdmGreeterLogOld.txt

** Attachment removed: "LightdmGreeterLog.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327201/+files/LightdmGreeterLog.txt

** Attachment removed: "LightdmDisplayLog.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327200/+files/LightdmDisplayLog.txt

** Attachment removed: "GconfCompiz.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327199/+files/GconfCompiz.txt

** Attachment removed: "DpkgLog.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327198/+files/DpkgLog.txt

** Attachment removed: "DkmsStatus.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327197/+files/DkmsStatus.txt

** Attachment removed: "Dependencies.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327196/+files/Dependencies.txt

** Attachment removed: "CurrentDmesg.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327195/+files/CurrentDmesg.txt

** Attachment removed: "BootLog.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327194/+files/BootLog.txt

** Attachment removed: "BootDmesg.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327193/+files/BootDmesg.txt

** Attachment removed: ".proc.driver.nvidia.params.txt"
   https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1389215/+attachment/4327192/+files/.proc.driver.nvidia.params.txt

-- 
You received this bug notification because you are a member of Desktop
Packages, which is subscribed to xorg in Ubuntu.
https://bugs.launchpad.net/bugs/1389215

Title:
  Brightness controls are not working in Unity / Xorg because of Nvidia
  proprietary driver.

Status in xorg package in Ubuntu:
  Incomplete

Bug description:
  Brightness controls are not working in Unity / Xorg.  When pressing
  the keys <fn><home> and <fn><end> on my Lenovo W510, I see the
  indicator on the screen showing the level of brightness changing, so
  key mapping is not the problem.  However, the brightness is not
  changing.

  On the kernel level, I have the single following device:

  # cd /sys/class/backlight
  # ls -l
  total 0
  lrwxrwxrwx 1 root root 0 Nov  3 17:16 acpi_video0 -> ../../devices/pci0000:00/0000:00:03.0/0000:01:00.0/backlight/acpi_video0

  When playing with the <fn><home> and <fn><end>, the value of
  /sys/class/backlight/brightness changes accordingly.  The screen
  brightness does not change.

  Performing:

  # echo 10 >brightness

  ...does not have any effect (regardless of the value provided, 10
  being just an example).

  WORKAROUND

  There is an odd workaround.  Simply go to the console using
  <CTRL><ALT><F1> and using the <fn><home> and <fn><end> keys,
  brightness then changes.  Return to Unity / Xorg with <CTRL><ALT><F7>
  and the selected brightness persists.

  NON WORKING WORKAROUND

  On the web, I read that adding:

  Option "RegistryDwords" "EnableBrightnessControl=1"'

  in xorg.conf might fix the problem.  I do not have an xorg and when I
  let the proprietary Nvidia driver generate one and add this option, X
  does not start anymore.

  Ubuntu 14.04.1 LTS with latest updates as of this writing.

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: xorg 1:7.7+1ubuntu8
  ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
  Uname: Linux 3.13.0-39-generic x86_64
  NonfreeKernelModules: nvidia
  .proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0'
  .proc.driver.nvidia.registry: Binary: ""
  .proc.driver.nvidia.version:
   NVRM version: NVIDIA UNIX x86_64 Kernel Module  331.38  Wed Jan  8 19:32:30 PST 2014
   GCC version:  gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
  .tmp.unity.support.test.0:

  ApportVersion: 2.14.1-0ubuntu3.5
  Architecture: amd64
  CompizPlugins: [core,bailer,detection,composite,opengl,compiztoolbox,decor,place,put,snap,resize,move,regex,session,vpswitch,imgpng,gnomecompat,text,ring,grid,mousepoll,animation,unitymtgrabhandles,wall,expo,ezoom,workarounds,fade,scale,unityshell]
  CompositorRunning: compiz
  CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
  CompositorUnredirectFSW: true
  CurrentDesktop: Unity
  Date: Tue Nov  4 07:38:59 2014
  DistUpgraded: Fresh install
  DistroCodename: trusty
  DistroVariant: ubuntu
  DkmsStatus:
   bbswitch, 0.7, 3.13.0-32-generic, x86_64: installed
   bbswitch, 0.7, 3.13.0-39-generic, x86_64: installed
   nvidia-331, 331.38, 3.13.0-32-generic, x86_64: installed
   nvidia-331, 331.38, 3.13.0-39-generic, x86_64: installed
   tp-smapi, 0.41, 3.13.0-32-generic, x86_64: installed
  ExtraDebuggingInterest: Yes
  GraphicsCard:
   NVIDIA Corporation GT216GLM [Quadro FX 880M] [10de:0a3c] (rev a2) (prog-if 00 [VGA controller])
     Subsystem: Lenovo Device [17aa:2145]
  InstallationDate: Installed on 2014-11-01 (3 days ago)
  InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
  MachineType: LENOVO 4318CTO
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-39-generic root=UUID=994f9c2c-f967-472e-ace3-23cd620ec702 ro quiet splash
  SourcePackage: xorg
  Symptom: display
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 10/03/2012
  dmi.bios.vendor: LENOVO
  dmi.bios.version: 6NET84WW (1.45 )
  dmi.board.name: 4318CTO
  dmi.board.vendor: LENOVO
  dmi.board.version: Not Available
  dmi.chassis.asset.tag: No Asset Information
  dmi.chassis.type: 10
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: Not Available
  dmi.modalias: dmi:bvnLENOVO:bvr6NET84WW(1.45):bd10/03/2012:svnLENOVO:pn4318CTO:pvrThinkPadW510:rvnLENOVO:rn4318CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
  dmi.product.name: 4318CTO
  dmi.product.version: ThinkPad W510
  dmi.sys.vendor: LENOVO
  version.compiz: compiz 1:0.9.11.2+14.04.20140714-0ubuntu1
  version.ia32-libs: ia32-libs N/A
  version.libdrm2: libdrm2 2.4.52-1
  version.libgl1-mesa-dri: libgl1-mesa-dri 10.1.3-0ubuntu0.1
  version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
  version.libgl1-mesa-glx: libgl1-mesa-glx 10.1.3-0ubuntu0.1
  version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
  version.xserver-xorg-core: xserver-xorg-core 2:1.15.1-0ubuntu2.1
  version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.8.2-1ubuntu2
  version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.3.0-1ubuntu3.1
  version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.910-0ubuntu1.1
  version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.10-1ubuntu2
  xserver.bootTime: Tue Nov  4 01:40:35 2014
  xserver.configfile: default
  xserver.errors: open /dev/fb0: No such file or directory
  xserver.logfile: /var/log/Xorg.0.log
  xserver.outputs:

  xserver.version: 2:1.15.1-0ubuntu2.1

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References

[Bug 1389215] [NEW] Brightness controls are not working in Unity / Xorg.
From: Hans Deragon, 2014-11-04