Hanging keys on Thinkpad

[Ludwig S.]

Under Ubuntu 18.04 the keys of my Thinkpad E480 are hanging very often. Then, instead of pressed once, the key seems to be not released and pressed continuously until another key is pressed. I have described the behavior in more detail under https://askubuntu.com/questions/1051508/hanging-keys-under-ubuntu-18-04.

It does not occur when I boot in Windows or Ubuntu 16.04, so it is not related to the hardware.
It does not occur when I plug in an external keyboard, so it is not related to general Ubuntu keyboard settings.
It does not occur when the power cable (USB-C) is unplugged, only when t is plugged in.

/var/log/syslog logs the following when the cable is plugged in:
"kernel: [ 9821.899727] thinkpad_acpi: EC reports that Thermal Table has changed"

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-32-generic 4.15.0-32.35
ProcVersionSignature: Ubuntu 4.15.0-32.35-generic 4.15.18
Uname: Linux 4.15.0-32-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: ludwig 1919 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Sun Aug 19 00:21:56 2018
InstallationDate: Installed on 2018-05-02 (108 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 003: ID 5986:2113 Acer, Inc
 Bus 001 Device 002: ID 046d:c046 Logitech, Inc. RX1000 Laser Mouse
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: LENOVO 20KQS00100
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-32-generic root=UUID=2ce0f255-4f53-4437-90ad-5e64f5a31b0f ro quiet splash vt.handoff=1
RelatedPackageVersions:
 linux-restricted-modules-4.15.0-32-generic N/A
 linux-backports-modules-4.15.0-32-generic N/A
 linux-firmware 1.173.1
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux
StagingDrivers: r8822be
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/27/2017
dmi.bios.vendor: LENOVO
dmi.bios.version: R0PET30W (1.07 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20KQS00100
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:bvrR0PET30W(1.07):bd11/27/2017:svnLENOVO:pn20KQS00100:pvrThinkPadE480:rvnLENOVO:rn20KQS00100:rvrNotDefined:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad E480
dmi.product.name: 20KQS00100
dmi.product.version: ThinkPad E480
dmi.sys.vendor: LENOVO

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

This change was made by a bot.

[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 v4.18 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/v4.18.3

[Ludwig S. (postlude)]

I didn't have access to internet for a while. Now I checked it with the upstream kernel v4.18.6. The bug still exists.

[Kai-Heng Feng (kaihengfeng)]

Can you try 4.4.x? That's what 16.04 ships.

[Ludwig S. (postlude)]

Thanks for the suggestion. I just tried kernel 4.4.157. The problem exists with this kernel as well.

[Kai-Heng Feng (kaihengfeng)]

Is it possible to try earlier linux kernel releases? So we can find where the regression begins.

[Ludwig S. (postlude)]

I've tried around a bit and found out that now, the problem occurred also in 16.04. Not sure if I just didn't try enough before or if the problems really wasn't there in 16.04 two months ago.

However, I've got the problem solved now. I updated the BIOS and the firmware using Lenovo system update from Windows and now, the problem is gone. So far, this works only for PCs with Windows but as recently published, Lenovo plans to provide native support for Linux for more and more Laptops. Maybe, the E480 will be supported too soon.
Thanks for the support!