[PATCH libinput 0/4] Fix synaptics cursor jumps for triple-touches

[Peter Hutterer]

Synaptics touchpads internally detect 5 touches but we use the serial
protocol in the kernel. That only allows for 2 slots so we get odd cursor
jumps whenever a third finger is put on the touchpad. Those come in two
varieties:
1) one slot ends when BTN_TOOL_TRIPLETAP is set and restarts as new touch on the
next event. Previously we only looked at fake touches when we exceed
num_slots (so libinput would think only one finger is down), patch 3/4
handles that case now.
2) during or immediately after a transition from TRIPLETAP to one or two
touches we'd get a coordinate jump. 4/4 filters those out now, causing a
more stable experience when three-finger tapping or clicking.

Cheers,
  Peter