How to use the laptop with lid closed (Linux)

I’m trying to use my FW13AMD with Fedora Linux in docked mode, i.e. lid closed, external monitor, keyboard and mouse etc. but every time I close the lid it immediately sleeps, and I’m unable to wake it with the keyboard or mouse. I’ve seen posts about this working under windows, so am I missing something? There didn’t seem to be any relevant settings in Gnome Settings