Touchscreen goes crazy after idle

[fabiocarneiro]

For some reason I wasn't able to identify, almost everytime ubuntu goes to lock screen, the touchscreen starts to randomly click everywhere. It eventually brings the on-screen keyboard and start typing whatever thing and keeps trying to log in.

At first, I got really scared because it really looks like a macro trying to authenticate and trying random passwords. But eventually, I realized it clicks in places that don't make sense and closes and open the keyboard several times.

I also thought it was just my screen being dirty, but I've been keeping it very clean and it happens multiple times immediately after cleaning and letting it idle. The issue was also being solved by cleaning but I think its just because in the process of cleaning I provide actual input, so it made me realize I can make it stop even without cleaning the screen by just touching somewhere.

I'm on Ubuntu 18.04. I usually run on Wayland because of the partial scaling and wasn't able to identify if it happens also on Xorg. Anyway, it usually happens on the lock screen, so I'm not sure whatever user initiated can influence that.

[rolandguelle]

Touchscreen or Touchpad? I never had this issue.

[fabiocarneiro]

Touchscreen

[BBBob]

I met this problem too. I use a script to disable the touchscreen before I close the lip on archlinux.

[fabiocarneiro]

@BBBob please share

[BBBob]

@fabiocarneiro

#!/bin/sh
declare -i ID
ID=`xinput | grep -Eio 'Touchscreen\s*id\=[0-9]{1,}' | grep -Eio 'id\=[0-9]{1,}'| grep -Eo '[0-9]{1,}'`
#ID=100
#echo ID:$ID
declare -i STATE
STATE=`xinput list-props $ID|grep 'Device Enabled'|awk '{print $4}'`
if [ $STATE -eq 1 ]
then
    xinput disable $ID
    echo "Touchscreen disabled."
    #notify-send 'Touchpad' 'Disabled' -i /usr/share/icons/Adwaita/48x48/devices/input-touchpad.png
    notify-send 'Touchscreen' 'Disabled' 
else
    xinput enable $ID
    echo "Touchscreen enabled."
    notify-send 'Touchscreen' 'Enabled' 
    #notify-send 'Touchpad' 'Enabled' -i /usr/share/icons/Adwaita/48x48/devices/input-touchpad.png
fi

maybe you need to modify something for your environment.

[jacobperron]

I am also experiencing this issue. Random touches are registered after going to the lock screen. Continues to happen after logging in and can sometimes be stopped by touching the screen.

[halfbyte]

Oh, interesting. I just recently started to experience this and was quite unsure about the origin, but I have to admit I never assumed it could be the touchscreen. I'll disable it to figure out if that's the culprit and will report back!

(Early 2018 Model, running stock Ubuntu 18.10)

[victorhearnyeates]

I also had this issue, easy fix was closing and reopening the lid

[Cethy]

Same here.
Solved by cycling between suspended and active state (I use the power button, but closing the lid like @victorhearnyeates suggests works too for me).

[jacobperron]

FWIW, I noticed this issue happening on Windows too. Closing the lid works for me.