This question is based on an assumption, so I'll start by explaining that. I am using a 4-port HDMI/USB KVM switch, and as long as I boot the systems while selected and with the monitor turned on, the display works just fine. If I reboot a system remotely, or if I have a different system selected when rebooting, I get no display when I select the impacted system(s). This is particularly true when coming back from a power failure, because all four are trying to boot at once, and obviously, I can only select one at a time, if I'm even there to have the monitor on at all. The keyboard seems to be working fine, in so far as I can tell working "blind". What I suspect is happening is that there must be some sort of conversation going on over the HDMI interface between the computer and the monitor and that some sort of configuration paramters are being determined. If that interpretation is correct, how can I capture those HDMI parameters and "hard code" them so that the display will function whether or not the system is selected on the KVM switch (or if the monitor is even turned on)? I am using Raspberry Pi 3B and 3B+, and have experienced the same behavior on FreeBSD 12.0, 12.1, and 13.0. Just FYI, it also happens with Rasbian Buster and Raspberry PI OS Bullseye, but I don't expect y'all to tackle that, even though a similar solution may apply.
