I've got a laptop using Linux Mint Cinnamon 20 and am trying to use an external keyboard. I've tried both wired and wireless keyboards but neither seem to work. I've tested both out on another pc and both work A-OK so it's not the devices and it's also obviously not the laptop's USB ports because I'm using a wired mouse which works fine. I just can't seem to get either keyboard to function. What can I do?