8086:0166 [Lenovo ThinkPad T530] Backlight control via fn-keys is stuck in certain ranges

[Benjamin Tegge]

I just upgraded my quantal installation on my Lenovo T530 to raring and found the backlight control via fn-keys not functioning properly as it did in quantal.

The backlight is initially set to 100% and can only be reduced to 95%. Setting the value to lower levels, brightness can the be controlled via fn-keys between 95% and 80%, 80% and 20%. The last range is from 20% to 0%. When booting raring with the quantal kernel, brightness can be controlled without issues.

The system is setup with UEFI and only Intel graphics (no hybrid). Clean MBR installation of raring to an external drive shows the same issue.
---
ApportVersion: 2.9.2-0ubuntu8
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: livewire 2491 F.... pulseaudio
CRDA:
 country DE:
  (2400 - 2483 @ 40), (N/A, 20)
  (5150 - 5250 @ 40), (N/A, 20), NO-OUTDOOR
  (5250 - 5350 @ 40), (N/A, 20), NO-OUTDOOR, DFS
  (5470 - 5725 @ 40), (N/A, 26), DFS
DistroRelease: Ubuntu 13.04
HibernationDevice: RESUME=UUID=75748ef4-e058-4ab6-be00-a6dd36ebcad0
InstallationDate: Installed on 2012-10-20 (190 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MachineType: LENOVO 2392CTO
MarkForUpload: True
Package: linux (not installed)
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-19-generic root=UUID=54762617-6f49-4a10-9c05-e6f9af033bd3 ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 3.8.0-19.29-generic 3.8.8
RelatedPackageVersions:
 linux-restricted-modules-3.8.0-19-generic N/A
 linux-backports-modules-3.8.0-19-generic N/A
 linux-firmware 1.106
Tags: raring
Uname: Linux 3.8.0-19-generic x86_64
UpgradeStatus: Upgraded to raring on 2013-04-28 (0 days ago)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
dmi.bios.date: 12/20/2012
dmi.bios.vendor: LENOVO
dmi.bios.version: G4ET90WW (2.50 )
dmi.board.asset.tag: Not Available
dmi.board.name: 2392CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrG4ET90WW(2.50):bd12/20/2012:svnLENOVO:pn2392CTO:pvrThinkPadT530:rvnLENOVO:rn2392CTO:rvrNotDefined:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 2392CTO
dmi.product.version: ThinkPad T530
dmi.sys.vendor: LENOVO

[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 1173984

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.

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[Benjamin Tegge (livewirebt)]

apport information

[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 v3.9 kernel[0].

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/v3.9-raring/

[Benjamin Tegge (livewirebt)]

I installed the kernel from the above link. Kernel is able to boot but issue persists.

[penalvch (penalvch)]

Benjamin Tegge, as per http://download.lenovo.com/express/ddfm.html an update is available for your BIOS (2.57). If you update to this following https://help.ubuntu.com/community/BiosUpdate , does it change anything? If it doesn't, could you please both specify what happened, and just provide the output of the following terminal command:
sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date

Please note your current BIOS is already in the Bug Description, so posting this on the old BIOS would not be helpful.

For more on BIOS updates and linux, please see https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette .

Thank you for your understanding.

[Benjamin Tegge (livewirebt)]

The issue does not occur anymore. It has been fixed, but not completely satisfactory, by a workaround in the kernel to use an older backlight control method than one comparable to Windows 8 which provides a more finegraned control. All in all backlight control support is back to the level of quantal in raring and saucy: functional.

I just tried to install the 2.57 update, but the updater told me that I already have the latest version.

$ sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date
G4ET97WW (2.57 )
10/17/2013

[penalvch (penalvch)]

Benjamin Tegge, this bug report is being closed due to your last comment https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1173984/comments/20 regarding this being fixed with an update. For future reference you can manage the status of your own bugs by clicking on the current status in the yellow line and then choosing a new status in the revealed drop down box. You can learn more about bug statuses at https://wiki.ubuntu.com/Bugs/Status. Thank you again for taking the time to report this bug and helping to make Ubuntu better. Please submit any future bugs you may find.