6.2.8 Bus drivers that produce at most one child in Start()
Some bus drivers are for bus controllers that have only a single port, so they
have at most one child handle. If RemainingDevicePath is NULL
, then that
one child handle should be produced. If RemainingDevicePath is not NULL
,
then the RemainingDevicePath should be parsed to see if it matches a device
path node that the bus driver knows how to produce.
For example, a serial port can have only one device attached to it. This device may be a terminal, a mouse, or a drill press, for example. The driver that consumes the Serial I/O Protocol from a handle must create a child handle with the produced protocol that uses the services of the Serial I/O Protocol.