I have a XPS 9550 and after rebooting while docked, USB devices don't work. After digging into it, when looking in the Device Manager, the ASMedia USB Root Hub isn't loaded. When I unplug, and replug it back in, the device is present.
This issue has been going on for some time, and I was waiting for an update to fix it, but it's been months and no such fix. It's frustrating having to replug my laptop into the dock everytime I want to restart (which also resets my display settings every time).
This is a great device, in theory, but in practice it has caused so many issues and so much time wasted just getting it to work.