Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?
Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.16 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'. 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/v4.16-rc7 ** Changed in: linux (Ubuntu) Importance: Undecided => Medium ** Changed in: linux (Ubuntu) Status: Confirmed => Incomplete -- 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/1758496 Title: Backlight does not work on a MacBookAir3,2 Status in linux package in Ubuntu: Incomplete Bug description: Backlight control does not work and there are no entries in /sys/class/backlight. When I boot my system with the option GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor" I can change the brightness with the command xrandr on a terminal. I attach all the system information about this problem. ProblemType: Bug DistroRelease: Ubuntu 17.10 Package: linux-image-4.13.0-37-generic 4.13.0-37.42 ProcVersionSignature: Ubuntu 4.13.0-37.42-generic 4.13.13 Uname: Linux 4.13.0-37-generic x86_64 ApportVersion: 2.20.7-0ubuntu3.7 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: victor 2932 F.... pulseaudio CurrentDesktop: ubuntu:GNOME Date: Sat Mar 24 07:22:05 2018 InstallationDate: Installed on 2018-03-04 (19 days ago) InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20180105.1) MachineType: Apple Inc. MacBookAir3,2 ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=es_ES.UTF-8 SHELL=/bin/bash ProcFB: 0 nouveaufb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-37-generic.efi.signed root=UUID=dd2bcce2-7d14-4df7-b7c8-6aea4fbb9c13 ro acpi_backlight=vendor RelatedPackageVersions: linux-restricted-modules-4.13.0-37-generic N/A linux-backports-modules-4.13.0-37-generic N/A linux-firmware 1.169.3 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 11/18/10 dmi.bios.vendor: Apple Inc. dmi.bios.version: MBA31.88Z.0061.B01.1011181342 dmi.board.asset.tag: Base Board Asset Tag# dmi.board.name: Mac-942C5DF58193131B dmi.board.vendor: Apple Inc. dmi.board.version: MacBookAir3,2 dmi.chassis.type: 10 dmi.chassis.vendor: Apple Inc. dmi.chassis.version: Mac-942C5DF58193131B dmi.modalias: dmi:bvnAppleInc.:bvrMBA31.88Z.0061.B01.1011181342:bd11/18/10:svnAppleInc.:pnMacBookAir3,2:pvr1.0:rvnAppleInc.:rnMac-942C5DF58193131B:rvrMacBookAir3,2:cvnAppleInc.:ct10:cvrMac-942C5DF58193131B: dmi.product.family: MacBook dmi.product.name: MacBookAir3,2 dmi.product.version: 1.0 dmi.sys.vendor: Apple Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1758496/+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