[NUC123] Reported USB intermittent enumeration failure

[alexclewontin]

@fishman I don't have any code to open a PR for your reported intermittent detection failure yet, so we can use this issue for discussion.

I still cannot reproduce it. When you experience this failure, how much traffic is being routed through the hub? Is the keyboard the only device, or are there others? When the keyboard failure occurs, do other devices passing through the hub continue to function normally?

Update: my USB hub appears to be on the fritz. I don't think I can reproduce (I've never had the USB hub detected but not the keyboard. I've tested the USB hub with some other devices, and I think the issue is an intermittent connection in the cable. It was cheap and you get what you pay for ¯\_(ツ)_/¯), but I have a new hub on the way, which should be helpful in diagnosis.