[Thinkpad T440S] The brightness is set to maximum after recovering from screen dimming or system suspend

[Jingguo Yao]

The brightness is set to maximum after recovering from the following two cases:

1) Recovering from system suspend.
2) Recovering from screen dimming.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-39-generic 3.13.0-39.66
ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
Uname: Linux 3.13.0-39-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: jing 2128 F.... pulseaudio
 /dev/snd/controlC0: jing 2128 F.... pulseaudio
CurrentDesktop: Unity
Date: Wed Nov 5 09:26:56 2014
HibernationDevice: RESUME=UUID=4bfed795-9c38-418e-b097-83b17523308e
InstallationDate: Installed on 2014-06-28 (129 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
MachineType: LENOVO 20AQA02QHH
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-39-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash acpi_backlight=vendor vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-39-generic N/A
 linux-backports-modules-3.13.0-39-generic N/A
 linux-firmware 1.127.7
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/21/2014
dmi.bios.vendor: LENOVO
dmi.bios.version: GJET72WW (2.22 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20AQA02QHH
dmi.board.vendor: LENOVO
dmi.board.version: 0B98405 STD
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrGJET72WW(2.22):bd02/21/2014:svnLENOVO:pn20AQA02QHH:pvrThinkPadT440s:rvnLENOVO:rn20AQA02QHH:rvr0B98405STD:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 20AQA02QHH
dmi.product.version: ThinkPad T440s
dmi.sys.vendor: LENOVO

[Brad Figg (brad-figg)]

This change was made by a bot.

[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 v3.18 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/v3.18-rc3-vivid/

[Jingguo Yao (yaojingguo)]

v3.18-rc3-vivid build fixes this bug.