To test different settings:
xinput list
xinput list-props 'Logitech Rechargeable Touchpad T650'
xinput set-prop 'Logitech Rechargeable Touchpad T650' 'Synaptics Finger' 1 12 0
xinput set-prop 'Logitech Rechargeable Touchpad T650' 'Synaptics Locked Drags' 1
xinput set-prop 'Logitech Rechargeable Touchpad T650' 'Synaptics Palm Detection' 1
To make it permanent:
# /usr/share/X11/xorg.conf.d/52-synaptics-t650.conf
Section "InputClass"
Identifier "Logitech Rechargeable Touchpad T650 quirks"
MatchProduct "Logitech Rechargeable Touchpad T650"
Option "FingerLow" "1"
Option "FingerHigh" "12"
Option "FingerPress" "0"
Option "LockedDrags" "on"
Option "PalmDetect" "on"
EndSection
References: