Looks like `example` managed to talk to evdi and connected to it. You didn't define DEBUG so the output is minimal.
Not sure why you're getting SIGILL for the Qt app, but it looks like you should perhaps update your pi (
https://github.com/raspberrypi/linux/issues/766).
Anyway. With the `example` running, play with `xrandr` to list available outputs and connectors, and see if reverse prime works.
So, in short, keep `example` in the background, and test the following:
- xrandr
- xrandr --listproviders
- xrandr --setprovideroutputsource 1 0
- xrandr --auto
...and see how far you get.
Regards,
Michal