It seems to be not related only to M3800 laptop but others like HP Spectre too. Regarding this topic I'm able to have a working touchscreen when I removed fwupd.
https://askubuntu.com/questions/1234975/touchscreen-stops-working-a-few- seconds-after-login-to-gnome-ubuntu-session-ubu I removed fwupd with the command "sudo apt remove fwupd" and rebooted the computer and now the touchscreen is working again. Do you need more informations ? -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-input-libinput in Ubuntu. https://bugs.launchpad.net/bugs/1886912 Title: DELL M3800 Touchscreen not working after login with fractional scaling. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libinput/+bug/1886912/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp