Elantech touchpad very slow and laggy with high CPU usage

Hi all,

I'm having an issue with an Elantech 1200 touchpad behaving poorly on
an asus laptop.  I think I can show that recording the touchpad with
hid-recorder delivers a clean event stream, but recording with
evemu-record produces the funky behaviour.

If anybody on here gets a chance, can you take a quick look at the bug
report I opened:
https://bugzilla.kernel.org/show_bug.cgi?id=198473

I would be very grateful for any tips on how to diagnose this further,
or any guesses as to what the problem could be.  Thanks in advance!

Best wishes,
Will Roberts