Section "InputClass"
    Identifier "Set mouse acceleration to zero"
    MatchIsPointer "on"
    MatchDevicePath "/dev/input/event*"

    # Default value of mouse acceleration: 2/1 4
    # Set AccelerationNumerator to zero to disable
    Option "AccelerationNumerator" "2"
    Option "AccelerationDenominator" "1"
    Option "AccelerationThreshold" "4"
EndSection