Decodes the what driver tracing is enabled.  Just because it
   is enabled does not mean it is active.  SDA tracing must be
   loaded and active.

   Format

      USB SHOW UHCI TRACE

1  –  Example

 SDA> usb sho uhci trace

 The following trace points are active  00000000000000ff
 -------------------------------------------------------
    Control requests
    Interrupt requests
    Bulk requests
    Make TD's for request active on controller
    Report setting for TD's toggles
    Completions of TD's
    Log everytime Interrupt Service Routine is called
    Normal successful interrupts
 -------------------------------------------------------