Macbook Air keyboard backlighting does not work on Ubuntu 18.10

[Mos]

Tested on a fresh installation of Ubuntu 18.10 and also on Ubuntu 18.10 Live.

The keyboard backlighting works fine on Ubuntu 18.04 and MacOS . Also tested `xset led 1` for 1 to 32 command and it does not work as well.

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: xorg 1:7.7+19ubuntu8
ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12
Uname: Linux 4.18.0-10-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.10-0ubuntu13
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Mon Oct 22 22:41:33 2018
DistUpgraded: Fresh install
DistroCodename: cosmic
DistroVariant: ubuntu
DkmsStatus: bcmwl, 6.30.223.271+bdcom, 4.18.0-10-generic, x86_64: installed
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Intel Corporation Haswell-ULT Integrated Graphics Controller [8086:0a26] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Apple Inc. Haswell-ULT Integrated Graphics Controller [106b:011b]
InstallationDate: Installed on 2018-10-20 (2 days ago)
InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3)
MachineType: Apple Inc. MacBookAir6,2
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.18.0-10-generic root=UUID=89e36b21-5540-440c-a145-16be978fa6ba ro quiet splash vt.handoff=1
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/08/2017
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBA61.88Z.0103.B00.1708080653
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-7DF21CB3ED6977E5
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookAir6,2
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-7DF21CB3ED6977E5
dmi.modalias: dmi:bvnAppleInc.:bvrMBA61.88Z.0103.B00.1708080653:bd08/08/2017:svnAppleInc.:pnMacBookAir6,2:pvr1.0:rvnAppleInc.:rnMac-7DF21CB3ED6977E5:rvrMacBookAir6,2:cvnAppleInc.:ct10:cvrMac-7DF21CB3ED6977E5:
dmi.product.family: MacBook Air
dmi.product.name: MacBookAir6,2
dmi.product.sku: System SKU#
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.95-1
version.libgl1-mesa-dri: libgl1-mesa-dri 18.2.2-0ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 18.2.2-0ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.20.1-3ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.1.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-3

[Cristian Aravena Romero (caravena)]

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
v4.19 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/v4.19-rc8

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1796550, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Feel free to continue to report any other bugs you may find.