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Thread
Date
[Bug 1400155] Re: inconsistent backlight brightness behaviour

To: kernel-packages@xxxxxxxxxxxxxxxxxxx
From: "Christopher M. Penalver" <christopher.m.penalver@xxxxxxxxx>
Date: Tue, 09 Dec 2014 01:16:46 -0000
Reply-to: Bug 1400155 <1400155@xxxxxxxxxxxxxxxxxx>
Sender: bounces@xxxxxxxxxxxxx
David Chatterton, could you please test the latest upstream kernel
available from the very top line at the top of the page (the release
names are irrelevant for testing, and please do not test the daily
folder) following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will
allow additional upstream developers to examine the issue.

If the test did not allow you to test to the issue (ex. you couldn't boot into the OS) please make a comment in your report about this, and continue to test the next most recent kernel version until you can test to the issue. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags:
kernel-fixed-upstream
kernel-fixed-upstream-VERSION-NUMBER

where VERSION-NUMBER is the version number of the kernel you tested exactly shown as:
kernel-fixed-upstream-3.18

This can be done by clicking on the yellow circle with a black pencil
icon next to the word Tags located at the bottom of the bug description.

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-VERSION-NUMBER

Once testing of the upstream kernel is complete, please mark this bug's
Status as Confirmed. Please let us know your results. Thank you for your
understanding.

** Attachment removed: "AlsaInfo.txt"
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** Description changed:

  This bug refers to a Dell XPS13-9333 running Ubuntu 14.10.
  
  I discovered a workaround to prevent the screen starting with full
  brightness.
  
- The reference to the workaround advice is: 
+ The reference to the workaround advice is:
  http://ubuntuhandbook.org/index.php/2014/04/save-screen-brightness-settings-in-ubuntu-14-04/
  
  There is a folder sys/class/backlight/intel_backlight/ containing a
  number of files such as brightness, actual_brightness and
  max_brightness. When using Fn-F4 & F5 to control the screen backlight,
  the two files: brightness and actual_brightness respond by changing
  there contents to a number which is a proportion of the contents of
  max_brightness (937).
  
  The workaround was to include the line:
  
-     echo 569 > /sys/class/backlight/intel_backlight/brightness
+     echo 569 > /sys/class/backlight/intel_backlight/brightness
  
  at the end of the file: /etc/rc.local using gedit (where 569 is a value
  noted for a typically comfortable level of backlight).
  
  This works when doing a restart but, when logging back in after logging
  out, the backlight comes on at maximum brightness.
  
  This particular laptop has a front-facing webcam fitted. Its function can be confirmed by running the Cheese webcam Booth. It would be a vast improvement if the ambient brightness could be sensed by the webcam and used to adjust the backlight brightness. Auto brightness could be selected or not by a tick box in the Brightness & Lock section of System Settings. Similarly, a tick box might also be provided to enable saving of the backlight brightness when shutting down or logging off
- --- 
+ ---
  ApportVersion: 2.14.7-0ubuntu8
  Architecture: amd64
  AudioDevicesInUse:
-  USER        PID ACCESS COMMAND
-  /dev/snd/controlC0:  david      2755 F.... pulseaudio
-  /dev/snd/controlC1:  david      2755 F.... pulseaudio
+  USER        PID ACCESS COMMAND
+  /dev/snd/controlC0:  david      2755 F.... pulseaudio
+  /dev/snd/controlC1:  david      2755 F.... pulseaudio
  CurrentDesktop: Unity
  DistributionChannelDescriptor:
-  # This is a distribution channel descriptor
-  # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
-  canonical-oem-somerville-precise-amd64-20130203-1
+  # This is a distribution channel descriptor
+  # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
+  canonical-oem-somerville-precise-amd64-20130203-1
  DistroRelease: Ubuntu 14.10
  HibernationDevice: RESUME=UUID=2ce4d026-79c8-46d8-aa78-9a01276f4ada
  InstallationDate: Installed on 2014-11-08 (29 days ago)
  InstallationMedia: Ubuntu 12.04 "Precise" - Build amd64 LIVE Binary 20130203-13:50
  MachineType: Dell Inc. XPS13 9333
  Package: linux (not installed)
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.16.0-25-generic root=UUID=10c98fc6-0c96-44d3-9e0e-ba93d84dffe6 ro quiet splash vt.handoff=7
  ProcVersionSignature: Ubuntu 3.16.0-25.33-generic 3.16.7
  RelatedPackageVersions:
-  linux-restricted-modules-3.16.0-25-generic N/A
-  linux-backports-modules-3.16.0-25-generic  N/A
-  linux-firmware                             1.138
+  linux-restricted-modules-3.16.0-25-generic N/A
+  linux-backports-modules-3.16.0-25-generic  N/A
+  linux-firmware                             1.138
  Tags:  utopic
  Uname: Linux 3.16.0-25-generic x86_64
  UpgradeStatus: Upgraded to utopic on 2014-11-21 (16 days ago)
  UserGroups: adm cdrom dialout dip libvirtd lpadmin plugdev sambashare sudo
  _MarkForUpload: True
  dmi.bios.date: 09/11/2014
  dmi.bios.vendor: Dell Inc.
  dmi.bios.version: A05
  dmi.board.name: 0D13CR
  dmi.board.vendor: Dell Inc.
  dmi.board.version: A00
  dmi.chassis.type: 8
  dmi.chassis.vendor: Dell Inc.
  dmi.chassis.version: 0.1
  dmi.modalias: dmi:bvnDellInc.:bvrA05:bd09/11/2014:svnDellInc.:pnXPS139333:pvr:rvnDellInc.:rn0D13CR:rvrA00:cvnDellInc.:ct8:cvr0.1:
  dmi.product.name: XPS13 9333
  dmi.sys.vendor: Dell Inc.
- --- 
- ApportVersion: 2.14.7-0ubuntu8
- Architecture: amd64
- AudioDevicesInUse:
-  USER        PID ACCESS COMMAND
-  /dev/snd/controlC0:  david      2755 F.... pulseaudio
-  /dev/snd/controlC1:  david      2755 F.... pulseaudio
- CurrentDesktop: Unity
- DistributionChannelDescriptor:
-  # This is a distribution channel descriptor
-  # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
-  canonical-oem-somerville-precise-amd64-20130203-1
- DistroRelease: Ubuntu 14.10
- HibernationDevice: RESUME=UUID=2ce4d026-79c8-46d8-aa78-9a01276f4ada
- InstallationDate: Installed on 2014-11-08 (29 days ago)
- InstallationMedia: Ubuntu 12.04 "Precise" - Build amd64 LIVE Binary 20130203-13:50
- MachineType: Dell Inc. XPS13 9333
- Package: linux (not installed)
- ProcFB: 0 inteldrmfb
- ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.16.0-25-generic root=UUID=10c98fc6-0c96-44d3-9e0e-ba93d84dffe6 ro quiet splash vt.handoff=7
- ProcVersionSignature: Ubuntu 3.16.0-25.33-generic 3.16.7
- RelatedPackageVersions:
-  linux-restricted-modules-3.16.0-25-generic N/A
-  linux-backports-modules-3.16.0-25-generic  N/A
-  linux-firmware                             1.138
- Tags:  utopic
- Uname: Linux 3.16.0-25-generic x86_64
- UpgradeStatus: Upgraded to utopic on 2014-11-21 (16 days ago)
- UserGroups: adm cdrom dialout dip libvirtd lpadmin plugdev sambashare sudo
- _MarkForUpload: True
- dmi.bios.date: 09/11/2014
- dmi.bios.vendor: Dell Inc.
- dmi.bios.version: A05
- dmi.board.name: 0D13CR
- dmi.board.vendor: Dell Inc.
- dmi.board.version: A00
- dmi.chassis.type: 8
- dmi.chassis.vendor: Dell Inc.
- dmi.chassis.version: 0.1
- dmi.modalias: dmi:bvnDellInc.:bvrA05:bd09/11/2014:svnDellInc.:pnXPS139333:pvr:rvnDellInc.:rn0D13CR:rvrA00:cvnDellInc.:ct8:cvr0.1:
- dmi.product.name: XPS13 9333
- dmi.sys.vendor: Dell Inc.

** Tags added: latest-bios-a04

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1400155

Title:
  inconsistent backlight brightness behaviour

Status in linux package in Ubuntu:
  Incomplete

Bug description:
  This bug refers to a Dell XPS13-9333 running Ubuntu 14.10.

  I discovered a workaround to prevent the screen starting with full
  brightness.

  The reference to the workaround advice is:
  http://ubuntuhandbook.org/index.php/2014/04/save-screen-brightness-settings-in-ubuntu-14-04/

  There is a folder sys/class/backlight/intel_backlight/ containing a
  number of files such as brightness, actual_brightness and
  max_brightness. When using Fn-F4 & F5 to control the screen backlight,
  the two files: brightness and actual_brightness respond by changing
  there contents to a number which is a proportion of the contents of
  max_brightness (937).

  The workaround was to include the line:

      echo 569 > /sys/class/backlight/intel_backlight/brightness

  at the end of the file: /etc/rc.local using gedit (where 569 is a
  value noted for a typically comfortable level of backlight).

  This works when doing a restart but, when logging back in after
  logging out, the backlight comes on at maximum brightness.

  This particular laptop has a front-facing webcam fitted. Its function can be confirmed by running the Cheese webcam Booth. It would be a vast improvement if the ambient brightness could be sensed by the webcam and used to adjust the backlight brightness. Auto brightness could be selected or not by a tick box in the Brightness & Lock section of System Settings. Similarly, a tick box might also be provided to enable saving of the backlight brightness when shutting down or logging off
  ---
  ApportVersion: 2.14.7-0ubuntu8
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  david      2755 F.... pulseaudio
   /dev/snd/controlC1:  david      2755 F.... pulseaudio
  CurrentDesktop: Unity
  DistributionChannelDescriptor:
   # This is a distribution channel descriptor
   # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
   canonical-oem-somerville-precise-amd64-20130203-1
  DistroRelease: Ubuntu 14.10
  HibernationDevice: RESUME=UUID=2ce4d026-79c8-46d8-aa78-9a01276f4ada
  InstallationDate: Installed on 2014-11-08 (29 days ago)
  InstallationMedia: Ubuntu 12.04 "Precise" - Build amd64 LIVE Binary 20130203-13:50
  MachineType: Dell Inc. XPS13 9333
  Package: linux (not installed)
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.16.0-25-generic root=UUID=10c98fc6-0c96-44d3-9e0e-ba93d84dffe6 ro quiet splash vt.handoff=7
  ProcVersionSignature: Ubuntu 3.16.0-25.33-generic 3.16.7
  RelatedPackageVersions:
   linux-restricted-modules-3.16.0-25-generic N/A
   linux-backports-modules-3.16.0-25-generic  N/A
   linux-firmware                             1.138
  Tags:  utopic
  Uname: Linux 3.16.0-25-generic x86_64
  UpgradeStatus: Upgraded to utopic on 2014-11-21 (16 days ago)
  UserGroups: adm cdrom dialout dip libvirtd lpadmin plugdev sambashare sudo
  _MarkForUpload: True
  dmi.bios.date: 09/11/2014
  dmi.bios.vendor: Dell Inc.
  dmi.bios.version: A05
  dmi.board.name: 0D13CR
  dmi.board.vendor: Dell Inc.
  dmi.board.version: A00
  dmi.chassis.type: 8
  dmi.chassis.vendor: Dell Inc.
  dmi.chassis.version: 0.1
  dmi.modalias: dmi:bvnDellInc.:bvrA05:bd09/11/2014:svnDellInc.:pnXPS139333:pvr:rvnDellInc.:rn0D13CR:rvrA00:cvnDellInc.:ct8:cvr0.1:
  dmi.product.name: XPS13 9333
  dmi.sys.vendor: Dell Inc.

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