Thinkpad T480 Touchpad gets locked in scroll mode

[Randy Syring]

My bug seems to be very similar to:

https://bugs.launchpad.net/dell-sputnik/+bug/1651635?comments=all

at least in terms of perceptible problems.

1. Occasionally, some type of interaction with the touchpad puts it into a mode where it barely works. Seems it gets stuck in "scroll mode" or something similar.
2. Happens a couple times a week.
3. In my case, it seems to happen by brushing my left palm in the upper left corner of the touchpad.
4. Symptom: gliding my finger across the touchpad like normal does not work. The middle and right side of the touchpad seem to be in scroll mode, i.e. I can scroll a browser window up & down but I can't move the pointer around. If I use the upper and left borders, the pointer seems to work as normal. Physical clicking works, right click in the lower right quadrant doesn't work. It's almost like the middle and right side of the touchpad are operating as if every touch is a two finger touch.
5. In the past, it seemed as if nothing but a restart would get it out of this mode. However, while filing this bug report, I just realized that repeated two finger scrolls in the middle of the touchpad seemed to unlock it from scroll mode. Then again, this could be a fluke of time or something, since I usually restart before I let the problem go on this long. I'll test more and report back here the next time it happens.

Happy to run commands to help troubleshoot.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xorg 1:7.7+19ubuntu14
ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
Uname: Linux 5.4.0-26-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CompositorRunning: None
CurrentDesktop: X-Cinnamon
Date: Sun May 3 13:50:55 2020
DistUpgraded: Fresh install
DistroCodename: focal
DistroVariant: ubuntu
DkmsStatus: virtualbox, 6.1.6: added
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation UHD Graphics 620 [8086:5917] (rev 07) (prog-if 00 [VGA controller])
   Subsystem: Lenovo UHD Graphics 620 [17aa:225d]
MachineType: LENOVO 20L5CTO1WW
ProcKernelCmdLine: \\vmlinuz-5.4.0-26-generic rw root=ZFS=sampro/ubuntu/root initrd=\initrd.img-5.4.0-26-generic
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/19/2020
dmi.bios.vendor: LENOVO
dmi.bios.version: N24ET56W (1.31 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20L5CTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: SDK0R32862 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrN24ET56W(1.31):bd02/19/2020:svnLENOVO:pn20L5CTO1WW:pvrThinkPadT480:rvnLENOVO:rn20L5CTO1WW:rvrSDK0R32862WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad T480
dmi.product.name: 20L5CTO1WW
dmi.product.sku: LENOVO_MT_20L5_BU_Think_FM_ThinkPad T480
dmi.product.version: ThinkPad T480
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.101-2
version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.4-2ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 20.0.4-2ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.20.8-2ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200226-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1

[Daniel van Vugt (vanvugt)]

I've seen similar happen on other machines before. It's probably a kernel bug or a hardware issue.

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

This change was made by a bot.