Like many universities, we are converting to working from home and
doing only online instruction as of Monday.  (This week is spring break and
faculty get to use it to figure out how to make the online instruction
work.)  The campus has a Zoom license and we are urged to use that for
class sessions.  I've run into a problem and tried the fix suggested by
Zoom support, but it's not working and I'm hoping someone here can help me.
Trying to interact with Zoom support gets a "we're too busy right now"
message....

The problem is sharing a window/screen (desktop).  I can share from my
Fedora desktop, but when I stop the sharing Zoom crashes (or, in some
configurations--see below--sharing a window/screen just blacks out the
window/screen being shared).   Zoom support indicates that this is mostly a
problem with something automatically switching from the nvidia card to a
built-in card and suggests running
   xcompmgr -c -l0 -t0 -r0 -o.00
With the nvidia driver, this seems to have little or no effect.   It does
seem to work with nouveau, but I'm getting an annoying flashing of (at
least some windows on) the screen with nouveau (and I'm losing some
performance that I'd like to keep for other purposes).

Here are the details:
[...]
I also have a Dell XPS 13 laptop running Fedora 31, also running KDE.  It
doesn't have this problem (but I hope not to have to use it for online
teaching; the screen is too small and it's one of the ones with the webcam
at the bottom of the screen, so if you can reach the keyboard to type, the
camera is looking up your nose). 

Thanks for any suggestions you can give me.

  George