How do I debug a detected but not working trackpad?

Question

I'm running Ubuntu 18.04.3 LTS on a Dell laptop with a built-in trackpad. All of a sudden, the trackpad has stopped working.

It is detected, but not sending any events.

xinput lists:

⎜ ↳ Synaptics TM3096-001 id=12 [slave pointer (2)]

Also, gnome-settings detects it, and I can change its options either via settings or xinput. But nothing has any actual effect.

I installed evtest and when I run that on the correct input event, it listens to events but none occur.

I've tried everything I've read about here - reloading certain kernel modules, disabling and reenabling the trackpad via xinput. There isn't a BIOS option for it, so I haven't been able to try switching it from "Advanced" to "Basic".

I'm not sure where to go with this, hence my question: how do I debug this? The similar solutions I've read usually involve not detecting a trackpad, or some feature not working. I've not found anything where the trackpad is detected but no events are being sent.

Edit: uname -a returns:

~% uname -a
Linux Xxxxxx 4.15.0-72-generic #81-Ubuntu SMP Tue Nov 26 12:20:02 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux