Can I configure my laptop's touchpad to only do scrolling?

Question

I have a Thinkpad which has both a TrackPoint mouse pointer (the little red thing between the G and H keys) and a Synaptics Touchpad.

I don't really like the Touchpad, and in fact keep swiping it accidentally, so I turned it off. But, there's one feature that's really nice: the two-finger scroll gesture.

Is there a way to make it so only this gesture works and all other input is ignored?

Answer 1

I couldn't get only two-finger scrolling to work, but I was able to expand the edge scrolling so it takes over the whole pad. That works for me. Here's what I did:

1) Enable edge scrolling vertically and horizontally, but not "coasting":

xinput --set-prop 'SynPS/2 Synaptics TouchPad'  'Synaptics Edge Scrolling' 1 1 0

2) Set the left and right "edges" of the trackpad to be 0. They default to being some value in the thousands, making a little border. Use xinput --list-props to find the initial values — the 4282 value for the bottom edge comes from that. I've also set the top edge to 0, on the grounds that that doesn't hurt.

 xinput --set-prop 'SynPS/2 Synaptics TouchPad'  'Synaptics Edges' 0 0 0 4282

3) Set the scrolling distance (amount your finger has to move before triggering a scroll event) to about double the default, because that was too fast:

 xinput --set-prop 'SynPS/2 Synaptics TouchPad'  'Synaptics Scrolling Distance' 250 250

With this, I can use the touchpad just to scroll, without it moving the cursor around. (And the high distance set above keeps me from triggering it accidentally.)