** 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-de...@lists.sourceforge.net 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
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1388817 Title: Backlight brightness problem with Thinkpad T440S To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1388817/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
