How oculus renders to the screen

I have two oculus rift and two rift compatible laptops. Just for fun I connected first oculus' USB to laptop 1 and HDMI to laptop 2, and second oculus' HDMI to laptop 1 and USB to laptop 2. In my opinion I should have got display on both oculus, but neither of them worked even when both laptops showed oculus as connected. I am still not sure why did that happen,  How is a scene rendered on oculus' screen and why did such cross connection fail?