[Samsung N220] Cannot control backlight using the keyboard keys on Ubuntu Server

[Ed Mente]

The problem appears in console mode only and it is that the backlight cannot be controlled with the Fn keys. It can neither be adjusted nor turned off. The Samsung N220 netbook runs Ubuntu Server 12.04.1 LTS and has a sun readable PixelQi display.

ls /sys/class/backlight :
intel_backlight
samsung

I have put acpi_backlight=vendor kernel parameter as setting acpi video backlight does not have any effect.

WORKAROUND: echo 200 |sudo dd of=/sys/class/backlight/intel_backlight/brightness
echo 4 |sudo dd of=/sys/class/backlight/samsung/brightness

The above commands work differently though. The first one allows controlling in great ranges, while the second controls the backlight within some bounds.

WORKAROUND: With the following kernel parameter the Fn keys function correctly:
acpi=off

---
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
AplayDevices: Error: [Errno 2] No such file or directory
ApportVersion: 2.0.1-0ubuntu15.1
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/by-path', '/dev/snd/controlC0', '/dev/snd/hwC0D0', '/dev/snd/pcmC0D0c', '/dev/snd/pcmC0D0p', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info: Error: [Errno 2] No such file or directory
Card0.Amixer.values: Error: [Errno 2] No such file or directory
DistroRelease: Ubuntu 12.04
EcryptfsInUse: Yes
HibernationDevice: RESUME=UUID=5222a4fe-9efb-4de0-823d-82a44027cb1f
InstallationMedia: Ubuntu-Server 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120817.3)
MachineType: SAMSUNG ELECTRONICS CO., LTD. N150/N210/N220
MarkForUpload: True
Package: linux (not installed)
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.2.0-29-generic root=UUID=a357370c-979e-45c4-954b-0d62b3dc9df5 ro acpi_backlight=vendor
ProcVersionSignature: Ubuntu 3.2.0-29.46-generic 3.2.24
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-29-generic N/A
 linux-backports-modules-3.2.0-29-generic N/A
 linux-firmware 1.79.1
RfKill: Error: [Errno 2] No such file or directory
Tags: precise
Uname: Linux 3.2.0-29-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
dmi.bios.date: 03/25/2010
dmi.bios.vendor: Phoenix Technologies Ltd.
dmi.bios.version: 08JI.M073.20100325.JIP
dmi.board.asset.tag: SAMSUNG
dmi.board.name: N150/N210/N220
dmi.board.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.board.version: Not Applicable
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenixTechnologiesLtd.:bvr08JI.M073.20100325.JIP:bd03/25/2010:svnSAMSUNGELECTRONICSCO.,LTD.:pnN150/N210/N220:pvrNotApplicable:rvnSAMSUNGELECTRONICSCO.,LTD.:rnN150/N210/N220:rvrNotApplicable:cvnSAMSUNGELECTRONICSCO.,LTD.:ct10:cvrN/A:
dmi.product.name: N150/N210/N220
dmi.product.version: Not Applicable
dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.7 kernel[0] (Not a kernel in the daily directory) and install both the linux-image and linux-image-extra .deb packages.

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.7-raring/

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1092517

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Ed Mente (ed1mente)]

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[penalvch (penalvch)]

Ed Mente, could you please test the latest upstream kernel available following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. Please do not test the daily folder, but the one all the way at the bottom. 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. For example:
kernel-fixed-upstream-v3.11-rc4

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. As well, please remove the tag:
needs-upstream-testing

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

As well, please remove the tag:
needs-upstream-testing

If you are unable to test the mainline kernel, please comment as to why specifically you were unable to test it and add the following tags:
kernel-unable-to-test-upstream
kernel-unable-to-test-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.

[Launchpad Janitor (janitor)]

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