I have an Intel desktop board with 975X chipset.
I was "playing" with the Microsoft Windows USB Device Viewer (UVCViewer.x86.exe).
I pluged different USB devices (one at a time) into the same physical connector on front panel of computer.
For example, plugging in a Wireless Receiver (for keyboard and mouse) the above viewer shows it on Controller 27CB, port 2.
If I plug an external HD into that same connector, the viewer shows it on Controller 27CC, port 8. (27CC is listed as a "USB2 Enahanced Host Controller" in Device Manager).
My question is does the power current requirement of the device determine the controller?
How can controllers be changed to control the same physical connector?
Google "USB Controller 27CC, port 8". I think you'll find your answer there.