how to disable certain features on synaptic touchpad

[ptoche]

I've had nightmares trying to set up my synaptic touchpad, on a brand-new (August 2010) Pavilion HP DV6-3048TX. I sort of managed on Windows, but am still struggling on a clean install and updated Kubuntu 10.4, install.

I have installed gpointing-device-synaptics, which is the recommended replacement for gsynaptics. It's in my autostart menu and works.

Here is the problem. I have reasons to believe it's something to do with the "multi touch" function. I have disabled tapping, scrolling, etc. and am just keeping the pointer feature.

I drag the pointer to the right of the screen with my right index finger. Now I touch the touchpad with my left index finger, while still holding my right index finger down. Then the pointer jumps sideways to the left, attracted by my left finger! The same thing happens from left to right.

I would like to disable this multi touch feature, instructing the touchpad to stay put whenever multiple touches are felt.

I don't have this problem on my other laptops, equipped with more primitive touchpads (the good old days), so I believe it's quite specific to the latest synaptics touchpad (I left a message on their forum a few weeks ago -- not a single reply).

Perhaps I need to go into some system settings file to access features gpointing-device-settings does not offer in the gui?

[ptoche]

Re: how to disable certain features on synaptic touchpad

here is a discussion that seems relevant to my problem, but as I don't want to mess things up unnecessarily, perhaps someone may tell me whether to go ahead with the recommendations.

http://forums.debian.net/viewtopic.php?f=16&t=50061

In particular, the following seems to be very relevant:

Postby demosthenese » 2010-04-06 02:45

I use the following script at login to set up my touchpad.

  #!/bin/bash

  # Set multi-touch emulation parameters
  xinput set-int-prop '"SynPS/2 Synaptics TouchPad"' "Synaptics Two-Finger Pressure" 32 10
  xinput set-int-prop '"SynPS/2 Synaptics TouchPad"' "Synaptics Two-Finger Width" 32 8
  xinput set-int-prop '"SynPS/2 Synaptics TouchPad"' "Two-Finger Scrolling" 8 1
  xinput set-int-prop '"SynPS/2 Synaptics TouchPad"' "Synaptics Two-Finger Scrolling" 8 1 1

  # Disable edge scrolling
  xinput set-int-prop '"SynPS/2 Synaptics TouchPad"' "Synaptics Edge Scrolling" 8 0 0 0

  # This will make cursor not to jump if you have two fingers on the touchpad and you lift one
  # (which you usually do after two-finger scrolling)
  xinput set-int-prop '"SynPS/2 Synaptics TouchPad"' "Synaptics Jumpy Cursor Threshold" 32 110


  # Set 1 2 and 3 finger taps
  xinput set-int-prop '"SynPS/2 Synaptics TouchPad"' "Synaptics Tap Action" 8 0 0 0 0 1 3 2

Can't remember where I lifted it from. You may need to change the name of the pointer device 'SynPS/2 ...' to the one reported by

xinput list

Edit:

a day after posting and xorg changes - above script now needs the double quotes around "'Syn...'" changed to single quotes 'Syn..' I remember thinking it odd that two sets of quotes were needed before.

Would you recommend this approach? thanks!

[The Liquidator]

Re: how to disable certain features on synaptic touchpad

I'm not sure how effective the gnome touchpad manager will be with KDE 4.

Have you tried the touchpad settings in system settings/input devices?

First place I would look is touch sensitivity and there are a n umber of settings for 2 fingered use.

HTH

[ptoche]

Re: how to disable certain features on synaptic touchpad

Thanks, The Liquidator.

This is where I've been: System Settings --> Keyboard&Mouse.

There I find 2 places --> Touchpad and Mouse.

1) Touchpad: I have the touchpad ON, everything else NOT ENABLED

2) Mouse --> Advanced

Pointer acceleration : 1.0x
Pointer threshold : 0 pixels
Double click interval : 0 pixels
Drag start time : 0 msec
Drag start distance : 1 pixel (can't get any lower)
Mouse wheel scrolls by : 3 lines

Am I in the right place? Can you suggest alternative settings you think would solve my problem?

thanks,

Patrick.

[The Liquidator]

Re: how to disable certain features on synaptic touchpad

Hi

Take a look under the scrolling tab in the touchpad section. There are 2 fingered scrolling options there - maybe they will help you.

[ptoche]

Re: how to disable certain features on synaptic touchpad

The Liquidator, thanks -- but I have disabled it all there.

I think I'm pretty close to nailing it, let me summarize what I've done.

Now, my understanding is the following: Kubuntu 10.4 no longer has a xorg.conf file in /etc/X11, but it does essentially the same thing by creating it on the fly, by compiling the conf files that are located in /usr/lib/X11/xorg.conf.d/. Correct me if I'm wrong.

In /usr/lib/X11/xorg.conf.d/ I have 4 files. Let me copy them here for reference.

05-evdev.conf

# Catchall classes for input devices
# We don't simply match on any device since that also adds accelerometers
# and other devices that we don't really want to use. The list below
# matches everything but joysticks.

Section "InputClass"
	Identifier "evdev pointer catchall"
	MatchIsPointer "on"
	MatchDevicePath "/dev/input/event*"
	Driver "evdev"
EndSection

Section "InputClass"
	Identifier "evdev keyboard catchall"
	MatchIsKeyboard "on"
	MatchDevicePath "/dev/input/event*"
	Driver "evdev"
EndSection

Section "InputClass"
	Identifier "evdev touchpad catchall"
	MatchIsTouchpad "on"
	MatchDevicePath "/dev/input/event*"
	Driver "evdev"
EndSection

Section "InputClass"
	Identifier "evdev tablet catchall"
	MatchIsTablet "on"
	MatchDevicePath "/dev/input/event*"
	Driver "evdev"
EndSection

Section "InputClass"
	Identifier "evdev touchscreen catchall"
	MatchIsTouchscreen "on"
	MatchDevicePath "/dev/input/event*"
	Driver "evdev"
EndSection

10-synaptics.conf:

Section "InputClass"
	Identifier "touchpad catchall"
	MatchIsTouchpad "on"
	MatchDevicePath "/dev/input/event*"
	Driver "synaptics"
EndSection

Section "InputClass"
	Identifier "Dell Inspiron embedded buttons quirks"
	MatchTag "inspiron_1011|inspiron_1012"
	MatchDevicePath "/dev/input/event*"
	Driver "synaptics"
	Option "JumpyCursorThreshold" "90"
	Option "AreaBottomEdge" "4100"
EndSection

Section "InputClass"
	Identifier "Dell Inspiron quirks"
	MatchTag "inspiron_1120"
	MatchDevicePath "/dev/input/event*"
	Driver "synaptics"
	Option "JumpyCursorThreshold" "250"
EndSection

Section "InputClass"
	Identifier "HP Mininote quirks"
	MatchTag "mininote_1000"
	MatchDevicePath "/dev/input/event*"
	Driver "synaptics"
	Option "JumpyCursorThreshold" "20"
EndSection

10-vmmouse.conf:

Section "InputClass"
	Identifier "vmmouse catchall"
	MatchTag "vmmouse"
	MatchDevicePath "/dev/input/event*"
	Driver "vmmouse"
EndSection

10-wacom.conf

Section "InputClass"
	Identifier "Wacom class"
	MatchProduct "Wacom|WACOM"
	MatchDevicePath "/dev/input/event*"
	Driver "wacom"
EndSection

Section "InputClass"
	Identifier "Wacom serial class"
	MatchProduct "Serial Wacom Tablet"
	Driver "wacom"
	Option "ForceDevice" "ISDV4"
EndSection

# N-Trig Duosense Electromagnetic Digitizer
Section "InputClass"
	Identifier "Wacom N-Trig class"
	MatchProduct "HID 1b96:0001"
	MatchDevicePath "/dev/input/event*"
	Driver "wacom"
EndSection

These files will be compiled in alpha-numeric order (or numeric-alphabetical number, whatever that's called), with the lower numbers first. So I thought I'd create a file named 10-mysynaptics.conf in which I would store my custom modifications. I did and after much trial and error managed to get my file read by the system.

As an aside, I often found myself unable to boot. I would boot on the DVD, select "try kubuntu without installing" and undo my changes thus. It took me a while to figure it out, so I'll consign it here for future reference. To access the hard drive from the DVD, in the konsole type cd /media/disk/ -- the odd thing was that for /disk to be present inside /media I first needed to launch Dolphin, navigate to the kubuntu partition and click on it. After the click, the konsole would "see" it.

So below is my 10-mysynaptics.conf file.

Section "InputClass"
	Identifier "touchpad catchall"
	MatchIsTouchpad "on"
	MatchDevicePath "/dev/input/event*"
	Driver "synaptics"
	Option		"LeftEdge"		"1752"	# X coordinate for left edge.
	Option		"RightEdge"		"5192"	# X coordinate for right edge #If set SpecialScrollAreaRight is ignored.
	Option		"TopEdge"		"1620"	# Y coordinate for top edge.
	Option		"BottomEdge"		"4236"	# Y coordinate for bottom edge.
#	Option		"SpecialScrollAreaRight""bool"	# Enable scroll region on the right edge as scroll wheel region.
	Option		"FingerLow"		"60"	# Finger pressure below this level triggers release.
	Option		"FingerHigh"		"61"	# Finger pressure above this level triggers touch.
	Option		"FingerPress"		"250"	# Finger pressure above this value triggers press.
#...							# A press is equivalent to putting touchpad in trackstick emulation mode.
	Option		"MaxTapTime"		"0"	# Max time in ms for detecting tap.
	Option		"BMaxTapMove"		"0"	# Max finger movement for detecting a tap.
	Option		"MaxDoubleTapTime"	"100"	# Max time in ms for detecting a double tap.
	Option		"SingleTapTimeout"	"100"	# Timeout after a tap to recognize it as a single tap.
	Option		"ClickTime"		"100"	# Duration of mouse click generated by tapping.
	Option		"FastTaps"		"false"	# Driver reacts faster to a single tap, double clicks caused by slow double tapping.
	Option		"VertScrollDelta"	"100"	# Edge-to-edge scroll distance of the vertical scroll.
	Option		"HorizScrollDelta"	"100"	# Edge-to-edge scroll distance of the horizontal scroll.
	Option		"VertEdgeScroll"	"false"	# Enable vertical scroll zone.
	Option		"HorizEdgeScroll"	"false"	# Enable horizontal scroll zone.
	Option		"CornerCoasting"	"false"	# Enable continuous scroll with finger in corner.
	Option		"CoastingSpeed"		"0"	# Corner coasting speed.
	Option		"VertTwoFingerScroll"	"false"	# Vertical scroll anywhere with two fingers.
	Option		"HorizTwoFingerScroll"	"false"	# Horizontal scroll anywhere with two fingers.
	Option		"MinSpeed"		"0.4"	# Speed factor for low pointer movement.
	Option		"MaxSpeed"		"0.6"	# Max speed factor for fast pointer movement.
	Option		"AccelFactor"		"0.01"	# Acceleration factor for normal pointer movements
	Option		"TrackstickSpeed"	"40"	# Speed scale in trackstick emulation mode.
	Option		"EdgeMotionMinZ"	"30"	# Finger pressure at which min edge motion speed is set.
	Option		"EdgeMotionMaxZ"	"150"	# Finger pressure at which max edge motion speed is set.
	Option		"EdgeMotionMinSpeed"	"1"	# Slowest setting for edge motion speed.
	Option		"EdgeMotionMaxSpeed"	"400"	# Fastest setting for edge motion speed.
	Option		"EdgeMotionUseAlways"	"false"	# If off, egde motion is used only when dragging. If on, also used for normal movements.
#	Option		"PressureMotionMinZ"	"int"	# Finger pressure at which minimum pressure motion factor is applied.
#	Option		"PressureMotionMaxZ"	"int"	# Finger pressure at which maximum pressure motion factor is applied.
#	Option		"PressureMotionMinFactor""int"	# Lowest setting for pressure motion factor. 
#	Option		"PressureMotionMaxFactor""int"	# Greatest setting for pressure motion factor.
 	Option		"UpDownScrolling"	"true"	# If on, the up/down buttons generate button 4/5 events. 
#...							# If off, the up button generates a double click, the down button generates a button 2 event. 
	Option		"LeftRightScrolling"	"true"	# If on, the left/right buttons generate button 6/7 events.  
#...							# If off, the left/right buttons both generate button 2 events.
	Option		"UpDownScrollRepeat"	"true"	# If on, when the up/down buttons are used for scrolling, will send auto-repeating 4/5 events, 
#...							# with the delay between repeats determined by ScrollButtonRepeat.
	Option		"LeftRightScrollRepeat"	"true"	# If on, when the left/right buttons are used for scrolling, will send auto-repeating 6/7 events
#...							# with the delay between repeats determined by ScrollButtonRepeat.
	Option		"ScrollButtonRepeat"	"100"	# Time in msec between repeats of button events 4-7 from the up/down/left/right scroll buttons.
	Option		"EmulateMidButtonTime"	"75"	# Maximum time in ms for middle button emulation.
	Option		"EmulateTwoFingerMinZ"	"280"	# For Alps touchpads, sets Z pressure threshold to emulate a two finger press.
	Option		"EmulateTwoFingerMinW"	"7"	# Some touchpads report a two-finger touch as wide finger. This emulates a two finger press. 
#...							# This feature works best with (PalmDetect) off. 
	Option		"TouchpadOff"		"2"	# Switch off the touchpad, enabled = 0 / switched off = 1 / only tapping and scrolling off \ 2.
	Option		"GuestMouseOff"		"0"	# Switch on/off guest mouse. 
	Option		"LockedDrags"		"0"	# If off, a tap and drag gesture ends when you release the finger. 
#...							# If on, the gesture is active until you tap a second time or until LockedDragTimeout expires.
	Option		"LockedDragTimeout"	"5000"	# How long in ms for the LockedDrags mode to be automatically turned off after finger is released.
	Option		"CircularScrolling"	"false"	# If on, circular scrolling is used.
	Option		"CircScrollDelta"	"30"	# Move angle (radians) of finger to generate a scroll event.
	Option		"CircScrollTrigger"	"0"	# Trigger region on the touchpad to start circular scrolling.
#...							# All Edges = 0. Top Edge = 1. Top Right Corner = 2. Right Edge = 3. Bottom Right Corner = 4.
#...							# Bottom Edge = 5. Bottom Left Corner = 6. Left Edge = 7. Top Left Corner = 8.
	Option		"RTCornerButton"	"1"	# Which mouse button is reported on a right top corner tap. Set to 0 to disable.
	Option		"RBCornerButton"	"1"	# Which mouse button is reported on a right bottom corner tap. Set to 0 to disable.
	Option		"LTCornerButton"	"1"	# Which mouse button is reported on a left top corner tap. Set to 0 to disable.
	Option		"LBCornerButton"	"1"	# Which mouse button is reported on a left bottom corner tap. Set to 0 to disable.
	Option		"TapButton1"		"1"
	Option		"TapButton2"		"2"
	Option		"TapButton3"		"3"
	Option		"PalmDetect"		"true"	# If palm detection should be enabled.
	Option		"PalmMinWidth"		"10"	# Minimum finger width at which touch is considered a palm.
 	Option		"PalmMinZ"		"200"	# Minimum finger pressure at which touch is considered a palm.
	Option		"GrabEventDevice"	"true" # If true, no other user space or kernel space program sees the touchpad events. 
#...							# This is desirable if the X config file includes /dev/input/mice as an input device.
#...							# This is undesirable if you want to monitor the device from user space. 
	Option		"TapAndDragGesture"	"false" # Switch on/off the tap-and-drag gesture. The gesture is enabled by default.
	Option		"AreaLeftEdge"		"0"	# Ignore movements, scrolling and tapping which take place left of this edge.
	Option		"AreaRightEdge"		"0"	# Ignore movements, scrolling and tapping which take place right of this edge. 
	Option		"AreaTopEdge"		"0"	# Ignore movements, scrolling and tapping which take place above this edge.
	Option		"AreaBottomEdge"	"0"	# Ignore movements, scrolling and tapping which take place below this edge. 
	Option		"JumpyCursorThreshold"	"0"	# Set the threshold above which movement events are ignored on single-touch touchpads. 
#...							# This option is disabled by default.
EndSection

I saved the text above as 10-mysynaptics.conf, and placed it in the proper place
sudo cp /usr/lib/X11/xorg.conf.d/10-mysynaptics.conf
sudo rm /usr/lib/X11/xorg.conf.d/10-synaptics.conf
and re-booted.

This loads properly on my system and with this procedure I'm totally in control of the parameters. I have selected mostly the default settings. Unfortunately, I still haven't fixed the problem. Let me describe the problem again: If I touch/tap/stroke the touchpad twice the pointer jumps. And I don't want that. And since I don't have this behaviour in Windows, it's not a hardware issue. I thought that the following would have fixed it, but no:

Option "VertTwoFingerScroll" "false" # Vertical scroll anywhere with two fingers.
Option "HorizTwoFingerScroll" "false" # Horizontal scroll anywhere with two fingers.

If anyone has any suggestion, I'll gladly experiment with different settings. Thanks!

[ptoche]

Re: how to disable certain features on synaptic touchpad [SOLVED!]

okay, here are the xorg.conf settings that did it for me (see my earlier post on how to make changes to xorg.conf):

# created by patrick in an attempt to gain control over synaptics touchpad
# August 2010. Kubuntu 10.4.
# sudo cp /usr/lib/X11/xorg.conf.d/10-mysynaptics.conf

Section "InputClass"
	Identifier "touchpad catchall"
	MatchIsTouchpad "on"
	MatchDevicePath "/dev/input/event*"
	Driver "synaptics"
	Option		"LeftEdge"		"1752"	# X coordinate for left edge.
	Option		"RightEdge"		"5192"	# X coordinate for right edge #If set SpecialScrollAreaRight is ignored.
	Option		"TopEdge"		"1620"	# Y coordinate for top edge.
	Option		"BottomEdge"		"4236"	# Y coordinate for bottom edge.
#	Option		"SpecialScrollAreaRight""bool"	# Enable scroll region on the right edge as scroll wheel region.
	Option		"FingerLow"		"30"	# Finger pressure below this level triggers release.
	Option		"FingerHigh"		"31"	# Finger pressure above this level triggers touch.
	Option		"FingerPress"		"250"	# Finger pressure above this value triggers press.
#...							# A press is equivalent to putting touchpad in trackstick emulation mode.
	Option		"MaxTapTime"		"200"	# Max time in ms for detecting tap.
	Option		"BMaxTapMove"		"100"	# Max finger movement for detecting a tap.
	Option		"MaxDoubleTapTime"	"100"	# Max time in ms for detecting a double tap.
	Option		"SingleTapTimeout"	"100"	# Timeout after a tap to recognize it as a single tap.
	Option		"ClickTime"		"100"	# Duration of mouse click generated by tapping.
	Option		"FastTaps"		"false"	# Driver reacts faster to a single tap, double clicks caused by slow double tapping.
	Option		"VertScrollDelta"	"100"	# Edge-to-edge scroll distance of the vertical scroll.
	Option		"HorizScrollDelta"	"100"	# Edge-to-edge scroll distance of the horizontal scroll.
	Option		"VertEdgeScroll"	"false"	# Enable vertical scroll zone.
	Option		"HorizEdgeScroll"	"false"	# Enable horizontal scroll zone.
	Option		"CornerCoasting"	"false"	# Enable continuous scroll with finger in corner.
	Option		"CoastingSpeed"		"0"	# Corner coasting speed.
	Option		"VertTwoFingerScroll"	"false"	# Vertical scroll anywhere with two fingers.
	Option		"HorizTwoFingerScroll"	"false"	# Horizontal scroll anywhere with two fingers.
	Option		"MinSpeed"		"0.4"	# Speed factor for low pointer movement.
	Option		"MaxSpeed"		"0.6"	# Max speed factor for fast pointer movement.
	Option		"AccelFactor"		"0.01"	# Acceleration factor for normal pointer movements
	Option		"TrackstickSpeed"	"40"	# Speed scale in trackstick emulation mode.
	Option		"EdgeMotionMinZ"	"30"	# Finger pressure at which min edge motion speed is set.
	Option		"EdgeMotionMaxZ"	"150"	# Finger pressure at which max edge motion speed is set.
	Option		"EdgeMotionMinSpeed"	"1"	# Slowest setting for edge motion speed.
	Option		"EdgeMotionMaxSpeed"	"400"	# Fastest setting for edge motion speed.
	Option		"EdgeMotionUseAlways"	"false"	# If off, egde motion is used only when dragging. If on, also used for normal movements.
	Option		"PressureMotionMinZ"	"50"	# Finger pressure at which minimum pressure motion factor is applied.
	Option		"PressureMotionMaxZ"	"150"	# Finger pressure at which maximum pressure motion factor is applied.
	Option		"PressureMotionMinFactor""1"	# Lowest setting for pressure motion factor. 
	Option		"PressureMotionMaxFactor""1"	# Greatest setting for pressure motion factor.
 	Option		"UpDownScrolling"	"true"	# If on, the up/down buttons generate button 4/5 events. 
#...							# If off, the up button generates a double click, the down button generates a button 2 event. 
	Option		"LeftRightScrolling"	"true"	# If on, the left/right buttons generate button 6/7 events.  
#...							# If off, the left/right buttons both generate button 2 events.
	Option		"UpDownScrollRepeat"	"true"	# If on, when the up/down buttons are used for scrolling, will send auto-repeating 4/5 events, 
#...							# with the delay between repeats determined by ScrollButtonRepeat.
	Option		"LeftRightScrollRepeat"	"true"	# If on, when the left/right buttons are used for scrolling, will send auto-repeating 6/7 events
#...							# with the delay between repeats determined by ScrollButtonRepeat.
	Option		"ScrollButtonRepeat"	"100"	# Time in msec between repeats of button events 4-7 from the up/down/left/right scroll buttons.
	Option		"EmulateMidButtonTime"	"500"	# Maximum time in ms for middle button emulation.
	Option		"EmulateTwoFingerMinZ"	"500"	# For Alps touchpads, sets Z pressure threshold to emulate a two finger press.
	Option		"EmulateTwoFingerMinW"	"500"	# Some touchpads report a two-finger touch as wide finger. This emulates a two finger press. 
#...							# This feature works best with (PalmDetect) off. 
	Option		"TouchpadOff"		"2"	# Switch off the touchpad, enabled = 0 / switched off = 1 / only tapping and scrolling off \ 2.
	Option		"GuestMouseOff"		"0"	# Switch on/off guest mouse. 
	Option		"LockedDrags"		"0"	# If off, a tap and drag gesture ends when you release the finger. 
#...							# If on, the gesture is active until you tap a second time or until LockedDragTimeout expires.
	Option		"LockedDragTimeout"	"5000"	# How long in ms for the LockedDrags mode to be automatically turned off after finger is released.
	Option		"CircularScrolling"	"false"	# If on, circular scrolling is used.
	Option		"CircScrollDelta"	"30"	# Move angle (radians) of finger to generate a scroll event.
	Option		"CircScrollTrigger"	"0"	# Trigger region on the touchpad to start circular scrolling.
#...							# All Edges = 0. Top Edge = 1. Top Right Corner = 2. Right Edge = 3. Bottom Right Corner = 4.
#...							# Bottom Edge = 5. Bottom Left Corner = 6. Left Edge = 7. Top Left Corner = 8.
	Option		"RTCornerButton"	"1"	# Which mouse button is reported on a right top corner tap. Set to 0 to disable.
	Option		"RBCornerButton"	"1"	# Which mouse button is reported on a right bottom corner tap. Set to 0 to disable.
	Option		"LTCornerButton"	"1"	# Which mouse button is reported on a left top corner tap. Set to 0 to disable.
	Option		"LBCornerButton"	"1"	# Which mouse button is reported on a left bottom corner tap. Set to 0 to disable.
	Option		"TapButton1"		"1"
	Option		"TapButton2"		"2"
	Option		"TapButton3"		"3"
	Option		"PalmDetect"		"true"	# If palm detection should be enabled.
	Option		"PalmMinWidth"		"10"	# Minimum finger width at which touch is considered a palm.
 	Option		"PalmMinZ"		"200"	# Minimum finger pressure at which touch is considered a palm.
	Option		"GrabEventDevice"	"true" # If true, no other user space or kernel space program sees the touchpad events. 
#...							# This is desirable if the X config file includes /dev/input/mice as an input device.
#...							# This is undesirable if you want to monitor the device from user space. 
	Option		"TapAndDragGesture"	"false" # Switch on/off the tap-and-drag gesture. The gesture is enabled by default.
	Option		"AreaLeftEdge"		"0"	# Ignore movements, scrolling and tapping which take place left of this edge.
	Option		"AreaRightEdge"		"0"	# Ignore movements, scrolling and tapping which take place right of this edge. 
	Option		"AreaTopEdge"		"0"	# Ignore movements, scrolling and tapping which take place above this edge.
	Option		"AreaBottomEdge"	"0"	# Ignore movements, scrolling and tapping which take place below this edge. 
	Option		"JumpyCursorThreshold"	"100"	# Set the threshold above which movement events are ignored on single-touch touchpads. 
#...							# This option is disabled by default.
EndSection

The key setting is most likely:
JumpyCursorThreshold = 100

but perhaps it is one of the following -- I changed them simultaneously and I'm afraid I can't now be bothered to experiment to see which does what.
EmulateMidButtonTime = 500
EmulateTwoFingerMinZ = 500
EmulateTwoFingerMinW = 500

I hope this information helps someone in the future. Now I can get started on my work!

[Megalex]

Re: how to disable certain features on synaptic touchpad

I have a similar issue. My Kubuntu keeps on displaying a "No touchpad detected" message upon start-up; my computer does not have a touchpad. How do I disable this auto-detection?