Got it. Basically we need to use ClutterBrightnessContrastEffect in GSD backlight to support brightness change for OLED systems.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1768208 Title: [Lenovo ThinkPad X1 Yoga 1st Gen] Can't change brightness Status in linux package in Ubuntu: Confirmed Bug description: The screen brightness cannot be changed. In 16.04, I could change the brightness via: xrandr --output eDP-1 --brightness 0.7 WORKAROUND: Execute at a terminal: xrandr --output eDP-1 --scale 1.25x1.25 --brightness 0.8 WORKAROUND: https://extensions.gnome.org/extension/1222/oled-dimmer/ --- ApportVersion: 2.20.9-0ubuntu7 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: marvin 1768 F.... pulseaudio CurrentDesktop: ubuntu:GNOME DistroRelease: Ubuntu 18.04 HibernationDevice: RESUME=UUID=e81e811a-12aa-465d-ba3c-77e34b171b69 MachineType: LENOVO 20FRS2M600 Package: linux (not installed) ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz root=/dev/nvme0n1p1 ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17 RelatedPackageVersions: linux-restricted-modules-4.15.0-20-generic N/A linux-backports-modules-4.15.0-20-generic N/A linux-firmware 1.173 Tags: bionic Uname: Linux 4.15.0-20-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo _MarkForUpload: True dmi.bios.date: 06/23/2016 dmi.bios.vendor: LENOVO dmi.bios.version: N1FET41W (1.15 ) dmi.board.asset.tag: Not Available dmi.board.name: 20FRS2M600 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: None dmi.modalias: dmi:bvnLENOVO:bvrN1FET41W(1.15):bd06/23/2016:svnLENOVO:pn20FRS2M600:pvrThinkPadX1Yoga1st:rvnLENOVO:rn20FRS2M600:rvrNotDefined:cvnLENOVO:ct10:cvrNone: dmi.product.family: ThinkPad X1 Yoga 1st dmi.product.name: 20FRS2M600 dmi.product.version: ThinkPad X1 Yoga 1st dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1768208/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp