I have a Surface Pro 3 and when I plug my Windows Phone into the USB port it doesn't connect or charge. I have a Lumina 920, but I have also tried my wifes phone (520 I think). I have tried different cables with no luck. I can plug the same phone into my Surface RT and it connects no problems.
The USB port on my Surface Pro 3 will power and work with a USB hard drive no problems.
Anybody else having any issues there?