I was looking into turning on drag lock so I could briefly lift my finger and reposition it to continue a tap-and-drag.
# get touchpad device id (12 in my case)
xinput --list
# get touchpad props
xinput list-props 12
# set libinput "Tapping Drag Lock Enabled"
xinput set-prop 12 280 1
This worked, though I figured I'd need to find a way to automate it, as I assumed the setting would be lost next time I restarted the machine. To test that hypothesis, I shut down and rebooted.
After the reboot, xinput list-props 12 shows Synaptics properties rather than libinput, as if the touchpad has changed its mind about which driver to use. For example, the drag-lock feature is listed as:
Synaptics Locked Drags (287): 0
Also, attempting to switch the touchpad to "natural scrolling" has no effect. Clarification I just realized that the gui isn't even showing an interface to set "natural scrolling" for the touchpad, only for the mouse.
How can I determine which driver is being used, and what might be changing that?
For reference, I'm running Gnome3 on Ubuntu 17.04