CentOS 7 current, TDE current.  Nvidia Quadro M2000 (4 x DP out), 2 x
Dell P2416D displays.

Applied patches last week and one of them (that seemed to be related
to the Nvidia proprietary drivers) blew up the system.  Eventually
ended up re-installing in an ultimately-failed bid to get productive
again (this is my work system).

Decided to forgo the Nvidia drivers and use the open source stuff.
Xrandr is a nightmare though, so I thought "well, just use the TDE
built-in screen controls".

Problem is that System Settings -> Monitor & Display can only see one
of the displays.  How do I get it to see the 2nd display?

Yes, it's plugged in.  Yes, I've checked "Enable global display
control".  Yes, I've clicked "Rescan Displays" (many times). "Test
Settings" gets me "xrandr: Failed to get size of gamma for output
default".

Not sure the system is seeing the first display correctly even though
it's working (I am typing this message on it) because while is sees
2560 x 1440 pixel, it thinks the refresh rate is 0 Hz (though, again,
its working).

Do I have to create and edit an Xorg.conf?  Because I tried that and
it didn't go well not to mention defeating the purpose of a "settings"
GUI ...


--
Peter Laws, BS, MRCP / N5UWY
National Weather Center / Network Operations Center
University of Oklahoma Information Technology
plaws@...