All notes
Synaptics

Intro

"synclient" command is much more powerful and GUI setting.

synclient [-lV?] [var1=value1 [var2=value2] ...]

-l	List current user settings. This is the default if no option is given.
-V	Print version number and exit.
-?	Show the help message.
var=value	Set user parameter var to value.

ArchWiki. To make it permanent, modify on /etc/X11/xorg.conf.d/50-synaptics.conf.

Section "InputClass"
	Identifier "touchpad catchall"
	Driver "synaptics"
	MatchIsTouchpad "on"
	Option "TapButton1" "1"
	Option "TapButton2" "2"
	Option "TapButton3" "3"
	Option "VertTwoFingerScroll" "1"
	Option "HorizTwoFingerScroll" "1"
	Option "VertScrollDelta" "-50"
	Option "HorizScrollDelta" "-50"
	Option "EmulateTwoFingerMinZ" "40"
	Option "EmulateTwoFingerMinW" "8"
	Option "CoastingSpeed" "0"
	Option "FingerLow" "35"
	Option "FingerHigh" "40"
	Option "PalmDetect" "1"
	Option "TouchpadOff" "0"
# This option is recommend on all Linux systems using evdev, but cannot be enabled by default. See the following link for details: http://who-t.blogspot.com/2010/11/how-to-ignore-configuration-errors.html
	MatchDevicePath "/dev/input/event*"
EndSection

synclient TapButton1="1"
synclient TapButton2="2"
synclient TapButton3="3"
synclient VertTwoFingerScroll="1"
synclient HorizTwoFingerScroll="1"
synclient VertScrollDelta="-50"
synclient HorizScrollDelta="-50"
synclient EmulateTwoFingerMinZ="40"
synclient EmulateTwoFingerMinW="8"
synclient CoastingSpeed="0"
synclient FingerLow="35"
synclient FingerHigh="40"
synclient PalmDetect="1" PalmMinWidth="5" PalmMinZ="20"
synclient TouchpadOff="0"
killall syndaemon
syndaemon -i 1 -d

Coasting

For explanation on options, see XOrgArchive.

Tap

Disable touchpad while typing

synclient PalmDetect=1

"PalmMinWidth" "integer": Minimum finger width at which touch is considered a palm.

"PalmMinZ" "integer": Minimum finger pressure at which touch is considered a palm.

killall syndaemon
#More aggressive behavior, allow for mod+key combos, enable mouse movements
# -i idle-time. Default is 2s.
# -k: Ignore modifier keys when monitoring keyboard activity.
# -K: Like -k but also ignore Modifier+Key combos.
# -t: Only disable tapping and scrolling, not mouse movements, in response to keyboard activity.
# -d: Start as a daemon, ie in the background.
syndaemon -i 0.2 -d