Set up KVM with default display during startup.
Set up KVM with default display during startup.
Hey there, I’m trying to tackle a strange problem with my Mac setup. I’m using a bunch of high-end components and a few different displays, but it’s all a bit confusing. Here’s what I have:
- **Mac specs:** NVIDIA 4080 Super, Asus ROG Strix Z790-A, 14700K, Thunderbolt EX4 card, Windows 11.
- **Displays:** Two LG 5K UltraThunderbolt panels, one Gigabyte Aorus FO32U2 on the PC, and a Mac that uses all three.
- **Connection setup:** I switch between the LG panel and the Gigabyte panel depending on what works. The PC uses DisplayPort pass-through to drive the Thunderbolt card from the GPU, while the Mac uses USB-C on the Gigabyte and HDMI on the PC.
- **Problem:** When I switch to the PC, it treats the LG panel as primary and the KVM doesn’t work at boot or when trying to wake up. I have to unplug the keyboard from the monitor, plug it directly into the PC, then power it up or log in—then move the cable back. It works fine once that’s done, except when logged out.
- **Goal:** I want the Mac to use the KVM features and have everything synchronized, especially during boot and BIOS. The Gigabyte should be the default display on Windows too.
I’m a cloud engineer, so I’m okay with advanced settings, but I’m more comfortable with Linux. Any suggestions? This is really puzzling.
Wow! You really nailed a tricky setup there. I’m not sure about the Mac, but I’m pretty sure setting up the main display on a PC before Windows starts is all about chance—and maybe a bit of magic. It seems the graphics card might have some built-in memory, and the first screen connected during BIOS boot becomes the default. I’m still looking for a way to adjust that primary choice, but so far nothing works. Hope this gives you a start!
No one offers a simple solution. Bios doesn't provide an option for connecting multiple graphics cards via cables, nor is it part of the graphics card program. You need to choose your hardware, some systems can't handle the BIOS resolution, which might explain why @thrasher_565 isn't seeing his bios. Is this really important? Are you looking for the bios display for looks or for troubleshooting, if you notice the screen later it’s easier to check. The latter means you can test each monitor separately. The cheaper and most common advice is to try swapping cables with the monitors (check that each monitor has its own slot, which isn't always possible depending on connectors). This explains why matching graphics cards and output types matter. I've found success using a mix of different 'hard' and 'soft' shutdowns and restarts while adjusting settings again, but as @Sawa Takahashi mentioned, it's risky.
some gpus feature a separate monitor port, while the older ones typically have both DP and DVI inputs—on the quad it seems it has DP and DVI, which is why the monitor uses DP. I can’t see the bios but notice the long display on the screen. Would switching to another GPU work? On my main system I have a 1080 with two identical DP ports, and even if I change cables, the center monitor still doesn’t show properly. The “mane” port is the issue.
Thanks for the advice. The main problem is that the keyboard doesn’t function with the KVM until the PC is logged in. I think if the monitor gets recognized sooner during boot, the KVM it supplies will activate earlier. That’s why I often disconnect the keyboard from the monitor, connect it directly to the PC, log in, and then reattach it. The BIOS doesn’t matter much at this point, maybe my approach is off.
Several events occurred. The following day after sharing this, the problem largely disappeared. It seems similar to when you bring your car to a mechanic and it stops making that strange sound. Regardless, I appreciate everyone's advice. Interestingly, once the KVM functioned properly, I encountered another issue where after sleeping the monitors failed to turn on at all. When waking from sleep, the mouse and keyboard activated, the fans turned on with RGB effects, and the monitors powered up but displayed nothing. The only fix was a hard reset of the machine. I experimented with different settings, but disabling the discrete TB card support in BIOS and using integrated graphics didn’t resolve it. Eventually, turning off the DTBT Go2SX Command in BIOS resolved everything—wakes from sleep, KVM works, everything is fine now. Back to gaming!