Como ativar e desativar o touchpad Debian

Instale.

apt install xserver-xorg-input-synaptics

Desligar
synclient TouchpadOff=1

Pode ser outro numero 80, 50, 60, synaptics.conf.

nano  /usr/share/X11/xorg.conf.d/70-synaptics.conf

Coloque no fim do arquivo.

Section "InputClass"
        Identifier      "Touchpad"                    
        MatchIsTouchpad "yes"                         
        Driver          "synaptics"                    
        Option          "AccelFactor"           "0.075"
        Option          "TapButton1"            "1"
        Option          "TapButton2"            "2"    
        Option          "TapButton3"            "3"    
        Option          "VertTwoFingerScroll"   "1"    
        Option          "HorizTwoFingerScroll"  "1"    
        Option          "VertEdgeScroll"        "1"
        Option          "CoastingSpeed"         "8"
        Option          "CornerCoasting"        "1"
        Option          "CircularScrolling"     "1"
        Option          "CircScrollTrigger"     "7"
        Option          "EdgeMotionUseAlways"   "1"
        Option          "LBCornerButton"        "8"    
        Option          "RBCornerButton"        "9"    
EndSection

Ligar

synclient TouchpadOff=0

Crie um arquivo assim como usuário comum para quando digitar (Desativar o Touchpad).

nano ~/.config/autostart/disable-touchpad-digitar.desktop


[Desktop Entry]

Encoding=UTF-8
Name=Disable touchpad while typing
Name[pt_BR]=Desativar touchpad durante a digitação
Exec=syndaemon -i 3 &
Icon=touchpad
Type=Application

su
senha

Agora crie um outro arquivo com root quando for conectar o mouse usb (Desativar e Ativa o Touchpad).

Crie mais um arquivo.

nano /etc/udev/rules.d/01-touchpad.rules

SUBSYSTEM=="input", KERNEL=="mouse[0-9]*", ATTRS{name}!="*TouchPad", ATTRS{name}!="*Stick", ACTION=="add", ENV{DISPLAY}=":0", ENV{XAUTHORITY}="/home/USER/.Xauthority", RUN+="/usr/bin/synclient TouchpadOff=1"
SUBSYSTEM=="input", KERNEL=="mouse[0-9]*", ATTRS{name}!="*TouchPad", ATTRS{name}!="*Stick", ACTION=="remove", ENV{DISPLAY}=":0", ENV{XAUTHORITY}="/home/USER/.Xauthority", RUN+="/usr/bin/synclient TouchpadOff=0"

Em USER coloque seu nome de usuário.

Reinicie o pc.
reboot

Fonte :: https://wiki.archlinux.org/index.php/Touchpad_Synaptics#Disabling_touchpad_on_plugged_in_mouse