Kernel 4.15.0 updates disabling touchscreen in tablet mode on X1 Yoga

[Cas]

After a linux kernel update to 4.15.0-32 the touchscreen on my X1 Yoga is disabled when rotated into tablet mode. This is a major regression since my laptop is unusable in tablet mode now. The touchscreen will work fine up until I rotate the screen 180 degrees and table mode is enabled.

Rebooting with kernel 4.15.0-30 restores the laptop to the correct behaviour.

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: calum 2459 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Mon Aug 20 22:28:50 2018
InstallationDate: Installed on 2017-10-20 (304 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20171018)
MachineType: LENOVO 20JDCTO1WW
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-32-generic root=UUID=4f03289b-2cac-4bfb-bc59-47e041629a44 ro quiet splash resume=UUID=4f03289b-2cac-4bfb-bc59-47e041629a44 resume_offset=757760 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
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/06/2018
dmi.bios.vendor: LENOVO
dmi.bios.version: N1NET42W (1.29 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20JDCTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40709 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 31
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrN1NET42W(1.29):bd07/06/2018:svnLENOVO:pn20JDCTO1WW:pvrThinkPadX1Yoga2nd:rvnLENOVO:rn20JDCTO1WW:rvrSDK0J40709WIN:cvnLENOVO:ct31:cvrNone:
dmi.product.family: ThinkPad X1 Yoga 2nd
dmi.product.name: 20JDCTO1WW
dmi.product.version: ThinkPad X1 Yoga 2nd
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 proposed kernel and post back if it resolves this bug?
See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed.

Thank you in advance!

[Cas (calumlind)]

Forgot about testing with proposed, thanks.

Installed 4.15.0-33 and that seems to fix the issue. :)

[Cas (calumlind)]

I am not sure what is going on but after restarting the bug has returned on 4.15.0-33 and remains on 4.15.0-34

[Cas (calumlind)]

Feel a bit silly, I just realised that a year ago I had created an event script to disable the touchpad in tablet mode due to thinkpad acpi driver bug. However I used the event number instead of a unique symlink and with kernel updates the event number remapped to the touchscreen and thus disabled it in tablet mode. All fixed now, sorry for noise!