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<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">First post on this list – don’t be too hard on me. <span style="font-family:Wingdings">
J</span><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I support a bunch of software developers that use a KVM to switch back and forth between a Windows workstation and a CentOS 7.9 workstation. The Windows side has dual monitors, both going through the KVM, and the Linux side has 3 monitors
– two monitors going through the KVM and the 3<sup>rd</sup> monitor connected directly to the PC.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In some cases, when they switch back and forth between the Windows PC and the Linux PC, the Linux PC loses its video resolution or 1 or more screens goes black. I’m assuming the video loses its sync with the monitor. To get out of this
state, the user usually does a CTRL-ALT-BACKSPACE to restart X, or they go to CTRL-ALT-F2, login from the command prompt, and type “startx”. In both cases they lose any unsaved work they’ve got open.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The video card (in most cases) is an NVIDIA 620 with the NVIDIA driver installed.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ve tried adding the following 4 lines to xorg.conf in the device section, and it seems to make only the left most monitor stable, but the other 2 monitors appear to be disabled, with black screens.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New""> Option "ConnectedMonitor" "DFP-0"<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New""> Option "CustomEDID" "DFP-0:/etc/X11/edid.bin"<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New""> Option "IgnoreEDID" "false"<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New""> Option "UseEDID" "true"<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The system sees the 3 monitors as DP-2, DP-0, and DP-6 (respectively, from left to right). The NVIDIA driver includes a GUI configuration app that lets you generate the EDID files on each of the monitors, so I created an edid.bin file for
each monitor, and adjusted the file path for each one in the 2<sup>nd</sup> line.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">There’s 3 device sections so I put the 4 lines above into each section (adjusting for edid.bin path and DP-x reference appropriately). That gave me one useable screen (the left one) – the middle and right monitor were black screens.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I tried putting the 4 lines all in one “Device” section, with the appropriate DP-x and edid.bin path, (total of 8 lines) and got the same result.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The PCs are Dell Optiplex 9020s, if that’s relevant.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any suggestions? Am I on the right track here or should I be trying something else?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">PG<o:p></o:p></p>
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