Hello everyone! I have an HP 15 laptop from mid 2017 that's been happily running Ubuntu MATE since 17.04 with no configuration issues. When I installed Ubuntu MATE 19.04, the built-in trackpad didn't work.
The suggestions here (from 12.04)
got the thing working for a single session.
The suggestions here (from 14.04)
got it working permanently. Instead of
psmouse.proto=bare
i did
psmouse.proto=imps
as per the other thread.
I had tried a bunch of other things earlier, including adding xserver-xorg-input-synaptics so I don't know if that's key too!
I hope this helps! This is literally the only problem I've had with Ubuntu MATE in the past 4 years, and it only affects this one computer