Needs a palm threshold of ~5 to detect based on touch size, we don't have anything else we can hook onto.
The current code requires use_touch_size enabled to activate palm size, but that shouldn't be necessary for this device - our lower threshold is 0 here.
And palm detection doesn't kick in on this device because it's an external touchpad. Need to extend this to cater for tablet touch devices.
Arguably having better touch arbitration here (Bug 104985) would work too, but only for the proximity-out scenario, not necessarily for the proximity-in scenario.
Author: Peter Hutterer <>
Date: Fri Feb 9 12:17:38 2018 +1000
touchpad: enable palm detection on tablets' touchpads