I have a workstation at a customer's place that I would like to operate remotely as well as locally. I have full access into the customer's network via VPN. The graphics adapter in the workstation has four ports, but the workstation has only three monitors attached. That is, one of the HDMI ports is not used yet.
The workstation runs Windows, and normally, I would simply access it remotely via Remote Desktop. But in this case, I need to unlock the HDD (which is fully encrypted) before booting the OS. Plus, I would like to be able to control the BIOS remotely as well as locally.
I have come to the conclusion that a PiKVM v3 would fit my needs quite well. Since this is not a hobby project, the cost would be OK (actually, I could get a ready-made device for 289 EUR right now). But I am concerned whether it will work as intended:
The question is at which HDMI port of the graphics card the PiKVM should be attached. As far as I know, graphics adapters direct the boot messages (or BIOS screens) to the output port where a monitor is actually connected. If multiple monitors are connected, the graphics adapter selects a "preferred" one and directs those messages to it.
Figuring out that "preferred" output port surely is not a problem, and neither is to attach the existing monitors to the other output ports in order to attach the PiKVM to the preferred one.
However, I am then afraid of what happens if I am at the local console. The graphics adapter would send the pre-boot output to the PiKVM in any case so that I wouldn't see it on any of the attached monitors when booting the machine.
Probably I could use a HDMI splitter to avoid that problem. I would attach the splitter's input to the preferred graphics adapter output port and connect the monitor in question and the PiKVM to the splitter's output ports.
But this in turn would cause other problems: The monitors that are currently in use have a resolution of 1920x1200 (and eventually will soon be replaced by 4K monitors), while the PiKVM can accept (i.e. offers to the host) 1920x1080 at maximum. Therefore, I probably would have to live with 1920x1080 on the monitor that's connected to the HDMI splitter, which is not acceptable.
I guess that this problem has a solution, but I am lacking some basic knowledge in this field because this is my first experience with KVM-over-IP. However, at this place, I'd like to state that I already have put quite some time into trying to find an answer myself. Unfortunately, this is a constellation that's not mentioned in any manual I've read.
How could I solve those problems?
I'd also like to state that this is not a request for a certain hardware or software recommendation. I just would like to learn about generic ways of solving this problem.
P.S.The workstation in question actually features a BMC / IPMI interface. But I don't want to use it due the catastrophic security design flaws in the respective specifications as well as in most implementations.
Edit / Update:
One of the commentators below suggested to use the HDMI passthrough of the PiVKM. This would be a valid approach, but there are two things against it:
First, the PiVKM 3 does not feature an HDMI passthrough. The PiKVM 4 does, but is nearly twice as expensive.
Second, and more important, I believe that the passthrough would only provide the resolution that the PiKVM can accept. That is, the resolution on the passthrough would still be limited to 1920x1080 even with a PiKVM v4. But I am unsure in this respect; I would be grateful if somebody would correct me if I am wrong.