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Message #87841
[Bug 1388817] Re: Backlight brightness problem with Thinkpad T440S
** Description changed:
At the beginning, I have the following four problems:
1. After every boot, the brightness is set to maximum.
2. The brightness can't be adjusted smoothly. Only 4 brightnesses can be achieved with Fn keys.
- 3. After recovering from dimming, the brightness is set to maximum.
+ 3. After recovering from screen dimming and system suspend, the brightness is set to maximum.
4. The following error message is printed during the boot:
[ 12.843633] thinkpad_acpi: Unsupported brightness interface, please contact ibm-acpi-devel@xxxxxxxxxxxxxxxxxxxxx
The following workaround fixes 1 for me.
http://askubuntu.com/questions/151651/brightness-is-reset-to-maximum-on-every-restart
I add "acpi_backlight=vendor" kernel parameter according to
https://wiki.ubuntu.com/Kernel/Debugging/Backlight. This fixes 2 and 3
for me.
But 4 still exists.
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/controlC0: jing 2280 F.... pulseaudio
- /dev/snd/controlC1: jing 2280 F.... pulseaudio
- /dev/snd/pcmC1D0p: jing 2280 F...m pulseaudio
+ USER PID ACCESS COMMAND
+ /dev/snd/controlC0: jing 2280 F.... pulseaudio
+ /dev/snd/controlC1: jing 2280 F.... pulseaudio
+ /dev/snd/pcmC1D0p: jing 2280 F...m pulseaudio
CurrentDesktop: Unity
Date: Mon Nov 3 20:51:08 2014
HibernationDevice: RESUME=UUID=4bfed795-9c38-418e-b097-83b17523308e
InstallationDate: Installed on 2014-06-28 (128 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
+ 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
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https://bugs.launchpad.net/bugs/1388817
Title:
Backlight brightness problem with Thinkpad T440S
Status in “linux” package in Ubuntu:
Confirmed
Bug description:
At the beginning, I have the following four problems:
1. After every boot, the brightness is set to maximum.
2. The brightness can't be adjusted smoothly. Only 4 brightnesses can be achieved with Fn keys.
3. After recovering from screen dimming and system suspend, the brightness is set to maximum.
4. The following error message is printed during the boot:
[ 12.843633] thinkpad_acpi: Unsupported brightness interface, please contact ibm-acpi-devel@xxxxxxxxxxxxxxxxxxxxx
The following workaround fixes 1 for me.
http://askubuntu.com/questions/151651/brightness-is-reset-to-maximum-on-every-restart
I add "acpi_backlight=vendor" kernel parameter according to
https://wiki.ubuntu.com/Kernel/Debugging/Backlight. This fixes 2 and 3
for me.
But 4 still exists.
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/controlC0: jing 2280 F.... pulseaudio
/dev/snd/controlC1: jing 2280 F.... pulseaudio
/dev/snd/pcmC1D0p: jing 2280 F...m pulseaudio
CurrentDesktop: Unity
Date: Mon Nov 3 20:51:08 2014
HibernationDevice: RESUME=UUID=4bfed795-9c38-418e-b097-83b17523308e
InstallationDate: Installed on 2014-06-28 (128 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
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References
