What happens when you connect a bad USB hub or cable to a Thunderbolt Display? Lot's of stuff. After setting up the display, I connected a FireWire 800 drive to the display1 and a USB3 drive to to the MacBook Pro.2
I experienced two kernel panics the first day. I also noticed that I could no longer restart while the Thunderbolt Display was connected. Finally, I started to notice that Spotlight services were not working properly. Searches just didn't work right. This has a serious impact on my best friend Hazel, which stopped processing files.
A short visit to the Console was enlightening.
Trial and error revealed the culprit. I've been using a Satchei USB hub with my old iMac.
I never had a single problem. I used it for the random USB connection and thumb drive. Apparently, the Thunderbolt Display has higher standards.
So, if you start seeing something like this, you've got a crappy $20 hub wrecking a $1000 monitor.
The IOUSBFamily is having trouble enumerating a USB device that has been plugged in. It will keep retrying.