Using my Logitech e3dPro with some hacks
Ubuntu 16/18 LTS
Arma3 version <= 1.80
1. Reboot PC with joystick disconnected
2. Connect joystick (usb in my case)
3. Run steam and go to bigpicture
4. Go to controller config, and map buttons for your device
5. Run Arma3 from bigpicture.
6. Joystick should appear in arma settings, disable it
7. Exit from Arma3, close bigpicture.
Done. On next run of Arma3 you should be able to map joystick actions in controls config.
Joystick should be connected right before playing. Joystick should be disconnected on each boot of OS