UEFI says "No keyboard detected" when using DP 1.4 KVM with USB-C

Hi everyone. I have a ROG Strix Z390-E Gaming motherboard that I updated to the latest BIOS version. I bought the 1.4 Display Port KVM Switch - Dual Monitor - Two Computer switch with USB-C Interface in order to swap between my laptop and my desktop whenever I need to.

However, my computer always says “No keyboard detected” during boot and I can’t use the keyboard or mouse to get into the UEFI. They only start working when I get to Windows. How can I get this to work? Could it have something to do with Legacy USB or Fast Boot being enabled? The only port that works for UEFI is the top right USB A port in the back.

I had a VERY similar Issue with my main desktop rig. I use a unicomp keyboard for classic IBM heritage goodness, and It wouldn’t recognise it. Then I plugged in a recentish Logitech keyboard and it booted no problem

Possibly a driver issue :thinking:
All I know is that ASUS bios seems to like my logitech for keyboard for whatever reason.

Will using a USB-C to A cable make the non-HID USB ports on the KVM slow too? They seem useful for adding a flash drive or external HDD/SSD to the computer.

can try the keyboard on a blue usb3 port, those are straight passthrough.

is the usbc cable a full usb3 type c cable? there are usb 2.0 type c cables and usb 3 type c cables and displayport type c cables and thunderbolt type c cables… so its a bit of a mess.

Ugh, tell me about it!

I’m using a USB-C to USB-C charging cable from my phone charger until I can get a 6 ft cable in the mail. Since the USB-C form factor does not have any markings, I can’t tell you what it is inside.

I have a similar situation. More info below, but first my workaround:
I keep an inexpensive keyboard permanently plugged in to another USB port. I never have to press any keys on this keyboard; just having it plugged in is enough to get the UEFI to work with the mouse and primary keyboard. (So I can put the 2nd keyboard on a shelf where it doesn’t take desk space.)

My primary keyboard is a Drop ENTR mechanical and is switched with an L1T KVM. This has worked fine with a half-dozen different computers at various times, but… My Unify X570 has some issue with the Drop keyboard, whether the KVM is used or not. Using only that keyboard, I can use the Delete key to enter the main UEFI screen - but from there, no response to keyboard or mouse.

The motherboard works fine with other USB keyboards I have tried, and having one of those keyboards plugged in allows the system to work as expected with the Drop keyboard.

You might consider trying something similar. Good luck.

Success! I used a USB-C to A cord plugged into the top right port on my motherboard and I plugged my keyboard into the USB 3 port on the KVM. Now I can get into the BIOS!

Thanks for your help everyone!

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Nevermind. It did not work. It only did that one time because I rebooted from the BIOS. I guess I am stuck fiddling with cables or using a second keyboard for BIOS. It will be annoying to live with “No Keyboard Detected” every time I boot, but oh well.

I feel like I should update this and say that ever since I got a new motherboard, this has been working perfectly! So the issue was an old MOBO all along.