When I move the touchpad right, the pointer moves left.
When I move the touchpad left, the pointer moves right.
When I move the touchpad up, the pointer moves down.
When I move the touchpad down, the pointer moves up.
The mouse pointer itself is upside-down.

I'm not sure I understand xinput well enough to get a working pointer
situation, several matracies have been attempted.

Workaround attempted:  Display itself was sideways, until I updated as
below:

root@felix:/etc/lightdm# grep -B 1 greeter_setup.sh lightdm.conf
[Seat:*]
greeter-setup-script=/etc/lightdm/greeter_setup.sh
root@felix:/etc/lightdm# ls -ld greeter_setup.sh
-rwxr-xr-x 1 root root 35 Sep 21 21:12 greeter_setup.sh
root@felix:/etc/lightdm# cat greeter_setup.sh
#!/bin/bash
xrandr -o right
exit 0
root@felix:/etc/lightdm#

However, righting the video did not make the pointer any more usable.

However, remaining are: