Reawakening a sleepy keyboard port

[Vague Assumption]

Have you ever noticed how it happens, sometimes, that when you haven't touched a computer's keyboard for a long time, the computer will become unresponsive to it? For example, if you've been RDP-ing to the server, and then you attach a keyboard to it, it won't respond to the keyboard until the computer's been rebooted?

Is there a way to reawaken the keyboard without rebooting the server? I can't reboot this computer and I'd really like to check on its console (It's not set up for RDP because previously, before 2/3 of them died from swelled capacitors, I had direct KVM connections.)

[Mi6t0]

Have you tried with an USB-keyboard :)?