I did the following:
synclient MinSpeed=0 MaxSpeed=0 HorizEdgeScroll=1 VertEdgeScroll=1 LeftEdge=1 RightEdge=2 TopEdge=1 BottomEdge=2
synclient TouchPadOff=1
touchpad=$(xinput list | sed -ne '/Touch/s,^.*id=\([0-9]*\).*$,\1,gp')
xinput set-prop $touchpad "Synaptics Coasting Speed" 0 0
xinput set-prop $touchpad "Synaptics Noise Cancellation" 50 50
xinput set-prop $touchpad "Device Enabled" 0
xinput list-props $touchpad
The output is:
Device 'AlpsPS/2 ALPS DualPoint TouchPad':
Device Enabled (135): 0
Coordinate Transformation Matrix (137): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
Device Accel Profile (264): 1
Device Accel Constant Deceleration (265): 2.500000
Device Accel Adaptive Deceleration (266): 1.000000
Device Accel Velocity Scaling (267): 12.500000
Synaptics Edges (289): 1, 2, 1, 2
Synaptics Finger (290): 12, 15, 0
Synaptics Tap Time (291): 180
Synaptics Tap Move (292): 107
Synaptics Tap Durations (293): 180, 180, 100
Synaptics ClickPad (294): 0
Synaptics Middle Button Timeout (295): 75
Synaptics Two-Finger Pressure (296): 141
Synaptics Two-Finger Width (297): 7
Synaptics Scrolling Distance (298): 48, 48
Synaptics Edge Scrolling (299): 1, 1, 0
Synaptics Two-Finger Scrolling (300): 1, 0
Synaptics Move Speed (301): 0.000000, 0.000000, 0.081934, 0.000000
Synaptics Off (302): 1
Synaptics Locked Drags (303): 0
Synaptics Locked Drags Timeout (304): 5000
Synaptics Tap Action (305): 0, 0, 0, 0, 0, 0, 0
Synaptics Click Action (306): 1, 1, 1
Synaptics Circular Scrolling (307): 0
Synaptics Circular Scrolling Distance (308): 0.100000
Synaptics Circular Scrolling Trigger (309): 0
Synaptics Circular Pad (310): 0
Synaptics Palm Detection (311): 0
Synaptics Palm Dimensions (312): 10, 100
Synaptics Coasting Speed (313): 0.000000, 0.000000
Synaptics Pressure Motion (314): ... of unknown type CARDINAL
Synaptics Pressure Motion Factor (315): 1.000000, 1.000000
Synaptics Grab Event Device (316): 0
Synaptics Gestures (317): 1
Synaptics Capabilities (318): 1, 1, 1, 1, 1, 1, 0
Synaptics Pad Resolution (319): 1, 1
Synaptics Area (320): 0, 0, 0, 0
Synaptics Noise Cancellation (321): 50, 50
Device Product ID (253): 2, 8
Device Node (254): "/dev/input/event7"
The touchpad still works, and touches act as clicks.