Keyboard backlight not working on Asus ZenBook Flip UX561UD laptop in Cosmic 18.10, works with 18.04.1 desktop installer live image

[Mario Vukelic]

Repro:
1. Press Fn+F3/F4 in fresh install from current Cosmic desktop image, fully updated

-> Keyboard backlight should come on or change but doesn't. The gnome-shell pop-up icon for the keyboard backlight appears for both keys, but the icon's "progress" bar is not visible.

Kernel version is linux-image-4.17.0-9-generic

This is the same in X and Wayland session. In case it matters, Nvidia binary drivers are installed but Nvidia is switched off via Prime setting in nvidia-settings. Running with Intel drivers

The keyboard backlight works perfectly when booting from the 18.04.1 desktop live image. When turning on light with 18.04.1, it is off again after rebooting into 18.10. (However 18.04.1 seems to freeze when shutting down from menu, I have to hard-shut it off).

Most other important Fn+Fx special keys on this laptop work (display brightness, touchpad off, sound) except for the airplane mode key. However the airplane mode key only fails in gnome-shell but works on the console (this is filed as https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1791367)
(Not working are a key that seems to mean "display off" and another of unclear purpose that never worked on any laptop I ever saw, maybe "presentation mode" as it seems to depict a flip chart or projection screen).

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: linux-image-4.17.0-9-generic 4.17.0-9.10
ProcVersionSignature: Ubuntu 4.17.0-9.10-generic 4.17.17
Uname: Linux 4.17.0-9-generic x86_64
ApportVersion: 2.20.10-0ubuntu9
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: angela 16196 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Fri Sep 7 22:08:12 2018
InstallationDate: Installed on 2018-09-05 (1 days ago)
InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Alpha amd64 (20180822)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 004: ID 8087:0a2b Intel Corp.
 Bus 001 Device 003: ID 13d3:5256 IMC Networks
 Bus 001 Device 002: ID 8644:800b Intenso GmbG Micro Line (4GB)
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: ASUSTeK COMPUTER INC. UX561UD
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.17.0-9-generic root=UUID=02bad6b5-ca8f-4184-b477-935995e14bdc ro quiet splash vt.handoff=1
RelatedPackageVersions:
 linux-restricted-modules-4.17.0-9-generic N/A
 linux-backports-modules-4.17.0-9-generic N/A
 linux-firmware 1.174
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/06/2018
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: UX561UD.304
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: UX561UD
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 31
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrUX561UD.304:bd03/06/2018:svnASUSTeKCOMPUTERINC.:pnUX561UD:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnUX561UD:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct31:cvr1.0:
dmi.product.family: ZenBook Flip
dmi.product.name: UX561UD
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.

[Mario Vukelic (kreuzsakra)]

Please let me know whatever I can do to help debug this

[Mario Vukelic (kreuzsakra)]

Bios version 304 is the latest from Asus

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Mario Vukelic (kreuzsakra)]

Added acpid as affected because there is a file /etc/acpi/asus-keyboard-backlight.sh so I suppose it will be involved

[Joseph Salisbury (jsalisbury)]

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-rc3

[Mario Vukelic (kreuzsakra)]

Absolutely, please allow a few days until I have access to the device it's not mine)

[Mario Vukelic (kreuzsakra)]

Fixed in mainline 4.19 rc4

[Mario Vukelic (kreuzsakra)]

To be clear, this should have been "it works in rc4". I didn't have time to test in which version the fix was committed.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Daniel van Vugt (vanvugt)]

Maybe merge with bug 1797862?

[Mario Vukelic (kreuzsakra)]

This bug was fixed in the package upower - 0.99.8-2ubuntu0.1 from Bug #1796550