Laptop: External monitor, keyboard, and mouse "disabled" -- how re-enable without rebooting?

[rhkramer@gmail.com]

I've installed Buster on a Dell Inspiron 1501 laptop.  I have it connected to 
an external monitor, keyboard, and mouse via a KVM switch.

I thouight all was well, but now, a day later (with the KVM switched to other 
computers), switching the KVM back to the laptop, the external monitor, 
keyboard, and mouse are no longer enabled.  (They still work fine for any of 
the other computers.)

I suspect that if I reboot the laptop, or maybe even if I logout of the 
current user and back in, I might get the external monitor, keyboard, and 
mouse re-enabled, but I don't really want to do either -- as is often the 
case, I have various files and such open and to an appropriate place that I 
don't want to lose (nor have to re-establish).

So, that leads to two questions:

1.  Is there a way to re-enable the external monitor, keyboard, and mouse 
without doing something like rebooting?

2. Is there a way (a setting to change) to keep the problem from recurring in 
the future?

One more  "extra credit" OT question (which I can ask in a future thread if no 
one responds here) -- how can I tell whether the Buster installation is using 
X or Wayland?