** Description changed:

- 
  Brightness Keys does not work on this system with 12.04.4.
  
  Brightness slider in "Settings > Brightness and Lock" does not function
  as well.
  
  There is two backlight interfaces under /sys/class/backlight/ :
  lrwxrwxrwx 1 root root 0 Apr 10 05:19 ideapad -> 
../../devices/platform/ideapad/backlight/ideapad
  lrwxrwxrwx 1 root root 0 Apr 10 05:19 intel_backlight -> 
../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-LVDS-1/intel_backlight
  
  Trying to modify brightness value directly in the control file, but only
  intel_backlight/brighness works here.
  
+ Further investigating by trying older kernel versions,
+ brightness hot keys and backlight interfaces works just fine with 3.2, 3.5, 
3.8 .
+ Verified with:
+ linux-image-3.2.0-60-generic               3.2.0-60.91
+ linux-image-3.5.0-48-generic               3.5.0-48.72~precise1               
          linux-image-3.8.0-38-generic               3.8.0-38.56~precise1       
                  
+ 
  ProblemType: Bug
  DistroRelease: Ubuntu 12.04
  Package: linux-image-3.11.0-15-generic 3.11.0-15.25~precise1 [modified: 
boot/vmlinuz-3.11.0-15-generic]
  ProcVersionSignature: Ubuntu 3.11.0-15.25~precise1-generic 3.11.10
  Uname: Linux 3.11.0-15-generic x86_64
  AlsaVersion: Advanced Linux Sound Architecture Driver Version 
k3.11.0-15-generic.
  ApportVersion: 2.0.1-0ubuntu17.6
  Architecture: amd64
  ArecordDevices:
-  **** List of CAPTURE Hardware Devices ****
-  card 0: PCH [HDA Intel PCH], device 0: ALC272 Analog [ALC272 Analog]
-    Subdevices: 1/1
-    Subdevice #0: subdevice #0
+  **** List of CAPTURE Hardware Devices ****
+  card 0: PCH [HDA Intel PCH], device 0: ALC272 Analog [ALC272 Analog]
+    Subdevices: 1/1
+    Subdevice #0: subdevice #0
  AudioDevicesInUse:
-  USER        PID ACCESS COMMAND
-  /dev/snd/controlC0:  ubuntu     1850 F.... pulseaudio
+  USER        PID ACCESS COMMAND
+  /dev/snd/controlC0:  ubuntu     1850 F.... pulseaudio
  CRDA: Error: [Errno 2] No such file or directory
  Card0.Amixer.info:
-  Card hw:0 'PCH'/'HDA Intel PCH at 0x90600000 irq 44'
-    Mixer name : 'Intel CougarPoint HDMI'
-    Components : 'HDA:10ec0272,17aa6012,00100001 
HDA:80862805,80860101,00100000'
-    Controls      : 28
-    Simple ctrls  : 10
+  Card hw:0 'PCH'/'HDA Intel PCH at 0x90600000 irq 44'
+    Mixer name : 'Intel CougarPoint HDMI'
+    Components : 'HDA:10ec0272,17aa6012,00100001 
HDA:80862805,80860101,00100000'
+    Controls      : 28
+    Simple ctrls  : 10
  Date: Thu Apr 10 05:22:31 2014
  HibernationDevice: RESUME=UUID=cfc777d4-9050-434e-8ea9-a22ea054c001
  InstallationMedia: Ubuntu 12.04.4 LTS "Precise Pangolin" - Release amd64 
(20140204)
  MachineType: LENOVO HuronRiver Platform
  MarkForUpload: True
  ProcEnviron:
-  TERM=xterm
-  PATH=(custom, no user)
-  LANG=en_US.UTF-8
-  SHELL=/bin/bash
+  TERM=xterm
+  PATH=(custom, no user)
+  LANG=en_US.UTF-8
+  SHELL=/bin/bash
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-15-generic 
root=UUID=74ea0650-a72e-4186-9064-5d3ad2e480d6 ro quiet splash 
acpi_backlight=vendor initcall_debug vt.handoff=7
  RelatedPackageVersions:
-  linux-restricted-modules-3.11.0-15-generic N/A
-  linux-backports-modules-3.11.0-15-generic  N/A
-  linux-firmware                             1.79.9
+  linux-restricted-modules-3.11.0-15-generic N/A
+  linux-backports-modules-3.11.0-15-generic  N/A
+  linux-firmware                             1.79.9
  SourcePackage: linux-lts-saucy
  StagingDrivers: rts5139
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 02/16/2012
  dmi.bios.vendor: LENOVO
  dmi.bios.version: 43CN45WW
  dmi.board.asset.tag: Base Board Asset Tag
  dmi.board.name: Emerald Lake
  dmi.board.vendor: LENOVO
  dmi.board.version: FAB1
  dmi.chassis.asset.tag: Asset Tag
  dmi.chassis.type: 10
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: 0.1
  dmi.modalias: 
dmi:bvnLENOVO:bvr43CN45WW:bd02/16/2012:svnLENOVO:pnHuronRiverPlatform:pvrLenovoB470e:rvnLENOVO:rnEmeraldLake:rvrFAB1:cvnLENOVO:ct10:cvr0.1:
  dmi.product.name: HuronRiver Platform
  dmi.product.version: Lenovo B470e
  dmi.sys.vendor: LENOVO

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

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https://bugs.launchpad.net/bugs/1305662

Title:
  [Lenovo B470e] Backlight interface does not working

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