[PATCH] USB: USB API documentation modification

 *

 * Host Controller Drivers (HCDs) place all the URBs for a particular

 * endpoint in a queue.  Normally the queue advances as the controller

 * hardware processes each request.  But when an URB terminates with any

 * fault (such as an error, or being unlinked) its queue stops, at least

 * until that URB's completion routine returns.  It is guaranteed that

 * the queue will not restart until all its unlinked URBs have been fully

 * retired, with their completion routines run, even if that's not until

 * some time after the original completion handler returns.

 * hardware processes each request.  But when an URB terminates with an

 * error its queue stops, at least until that URB's completion routine

 * returns.  It is guaranteed that the queue will not restart until all

 * its unlinked URBs have been fully retired, with their completion

 * routines run, even if that's not until some time after the original

 * completion handler returns.  Normally the same behavior and guarantees

 * apply when an URB terminates because it was unlinked; however if an

 * URB is unlinked before the hardware has started to execute it, then

 * its queue is not guaranteed to stop until all the preceding URBs have

 * completed.

 *

 * This means that USB device drivers can safely build deep queues for

 * large or complex transfers, and clean them up reliably after any sort