Некоторые проблемы совместной работы мыши и Touchpad можно решить,
добавив параметр загрузки ядра:
   psmouse.proto=imps

Ниже пример настройки  Touchpad и внешней мыши для X.Org:

# Тачпад
Section "InputDevice"
  Driver        "synaptics"
  Identifier    "Mouse2"
  Option        "Device"        "/dev/psaux"
  Option        "Edges"         "1900 5400 1800 3900"
  Option        "Finger"        "25 30"
  Option        "MaxTapTime" "20"
  Option        "MaxTapMove" "220"
  Option        "VertScrollDelta" "100"
  Option        "MinSpeed"      "0.02"
  Option        "MaxSpeed"      "0.18"
  Option        "AccelFactor" "0.0010"
EndSection

# USB мышь
Section "InputDevice"
    Identifier          "Mouse1"
    Driver              "mouse"
    Option              "Protocol"    "IMPS/2"
    Option              "Device"      "/dev/input/mice"
    Option              "ZAxisMapping" "4 5"
    Option              "Buttons" "5"
EndSection

Section "ServerLayout"
   ....
    InputDevice "Mouse2" "CorePointer"
    InputDevice "Mouse1" "SendCoreEvents"
EndSection