Ubuntu 17.10: Lid closing disables touchpad, how to fix?

Solution 1:

Turns out it was a kernel bug. As reported by Askar Timirgazin in How to run sudo .sh file after wakeup : Touchpad disabled after upgrading to Ubuntu 17.10, the bug was fixed by updating the kernel to 4.13.7.

TL;DR

Download the following kernel updates.

http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.13.7/linux-headers-4.13.7-041307_4.13.7-041307.201711060248_all.deb

http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.13.7/linux-headers-4.13.7-041307-generic_4.13.7-041307.201711060248_amd64.deb

http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.13.7/linux-image-4.13.7-041307-generic_4.13.7-041307.201711060248_amd64.deb

Install them with dpkg -i

Run sudo reboot

You should be able to use your mousepad.

Sources:

http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.13.7/

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1723799