I have a Dell server with a Quadro K2200, it has two DisplayPort interfaces. Each DisplayPort is connected to a KVM-over-IP sender (it sends the display signal over IP), which itself connects to a local network.On the other side of the network there are several terminals. Each terminal has two screens with a KVM-over-ip receiver for each screen. The idea is being able to control the server remotely using the KVM communication.The problem arises when I switch from one terminal to the other. The graphics card somehow messes up and doesn't properly detect the re-connection. I've configured the X server so that there's the least possible automation, I've disabled EDID and I've limited the allowed interfaces. However, when I switch the processor from one terminal to the other (which is doing using a propietary API in the KVM devices), the desktop manager detects that one of the screens has been disconnected but fails to detect that a second one gets reconnected.I've checked udevadm monitor to see what happens when I switch from one terminal to the other, but there are no events. The Xorg log effectively shows the disconnection and the reconnection. According to the Nvidia docs, the UseHotplugEvents cannot be disabled for DisplayPort ports. This is the relevant part of my xorgs.conf:Section Screen                                                                                                                                                                                  Identifier     Screen0                                                                                                                                                                      Device         Device0                                                                                                                                                                      Monitor        Monitor0                                                                                                                                                                     DefaultDepth    24                                                                                                                                                                            Option         Stereo 0                                                                                                                                                                   Option         nvidiaXineramaInfoOrder DFP-1                                                                                                                                              Option         metamodes DP-0: 1920X1080 +0+0, DP-1: 1920X1080 +1920+0                                                                                                                    Option         SLI Off                                                                                                                                                                    Option         MultiGPU Off                                                                                                                                                               Option         BaseMosaic off                                                                                                                                                             SubSection     Display                                                                                                                                                                          Depth       24                                                                                                                                                                                Virtual    3840 1080                                                                                                                                                                      EndSubSection                                                                                                                                                                                 Option         UseEDID FALSE                                                                                                                                                              Option       UseEDIDFreqs false                                                                                                                                                           Option         ConnectedMonitor GPU-0.DFP-1,GPU-0.DFP-2                                                                                                                                   Option         UseDisplayDevice GPU-0.DFP-1,GPU-0.DFP-2                                                                                                                                   Option         UseHotplugEvents FALSE                                                                                                                                                    Option         AllowEmptyInitialConfiguration TRUE                                                                                                                                        Option         ExactModeTimingsDVI TRUE                                                                                                                                               EndSection                                                                                                                                                                                    Section Monitor                                                                                                                                                                                     Identifier Monitor0                                                                                                                                                                         ModelName DELL S2415H                                                                                                                                                                       VendorName DEL                                                                                                                                                                              # Monitor Manufactured week 36 of 2016                                                                                                                                                        # EDID version 1.3                                                                                                                                                                            # Digital Display                                                                                                                                                                             DisplaySize 530 300                                                                                                                                                                           Gamma 2.20                                                                                                                                                                                    Option DPMS true                                                                                                                                                                          Horizsync 30-83                                                                                                                                                                               VertRefresh 56-76                                                                                                                                                                             # Maximum pixel clock is 170MHz                                                                                                                                                               #Not giving standard mode: 1152x864, 75Hz                                                                                                                                                     #Not giving standard mode: 1280x1024, 60Hz                                                                                                                                                    #Not giving standard mode: 1600x900, 60Hz                                                                                                                                                     #Not giving standard mode: 1600x1200, 60Hz                                                                                                                                                    #Not giving standard mode: 1920x1080, 60Hz                                                                                                                                                                                                                                                                                                                                                  #Extension block found. Parsing...                                                                                                                                                            Modeline        1920x1080 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync                                                                                                      Modeline        Mode 0 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync                                                                                                         Modeline        Mode 1 148.500 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync                                                                                                        Modeline        Mode 2 74.250 1920 2008 2052 2200 1080 1082 1087 1125 +hsync +vsync interlace                                                                                               Modeline        Mode 3 74.250 1280 1390 1420 1650 720 725 730 750 +hsync +vsync                                                                                                             Modeline        Mode 4 27.027 720 736 798 858 480 489 495 525 -hsync -vsync                                                                                                                 Modeline        Mode 5 27.027 720 736 798 858 480 489 495 525 -hsync -vsync                                                                                                                 Modeline        Mode 6 27.027 1440 1478 1602 1716 480 484 487 525 -hsync -vsync interlace                                                                                                   Modeline        Mode 7 27.000 1440 1464 1590 1728 576 578 581 625 -hsync -vsync interlace                                                                                                   Modeline        Mode 8 25.200 640 656 752 800 480 490 492 525 -hsync -vsync                                                                                                                 Modeline        Mode 9 74.250 1920 2448 2492 2640 1080 1082 1089 1125 +hsync +vsync interlace                                                                                               Modeline        Mode 10 148.500 1920 2448 2492 2640 1080 1084 1089 1125 +hsync +vsync                                                                                                       Modeline        Mode 11 27.000 720 732 796 864 576 581 586 625 -hsync -vsync                                                                                                                Modeline        Mode 12 74.250 1280 1720 1760 1980 720 725 730 750 +hsync +vsync                                                                                                            Modeline        Mode 14 74.25 1920 2008 2052 2200 540 542 547 562 +hsync +vsync interlace                                                                                                   Modeline        Mode 15 74.25 1280 1390 1430 1650 720 725 730 750 +hsync +vsync                                                                                                             Modeline        Mode 16 27.00 720 736 798 858 480 489 495 525 -hsync -vsync                                                                                                                 Option PreferredMode 1920x1080                                                                                                                                                            Option  UseEDID FALSE                                                                                                                                                             EndSection                                                                                                                                                                                    To get by, I have a script that runs xrandr, it's simply a loop running: DISPLAY=:0 xrandr --output DP-0 --mode 1920x1080 --output DP-1 --mode 1920x1080 --right-of DP-0But that's an ugly solution. It'd be great if the window manager didn't realise about the screen switch. It that weren't possible, at least I'd like to have a udev event so that I can launch the script in that precise moment instead of having it running forever.
RHEL, monitor/disable hotplug screen detection with NVIDIA driver
x11;xorg;nvidia