Intel Extensible Firmware Interface - Manual (Page 569)

Protocols — USB Support
Version 1.10 12/01/02 14-29
Description
This function is used to retrieve the status of the root hub port specified by PortNumber .
EFI_USB_PORT_STATUS describes the port status of a specified USB port. This data structure is
designed to be common to both a USB root hub port and a USB hub port.
The number of root hub ports attached to the USB host controller can be determined with the
function
GetRootHubPortNumber() . If PortNumber is greater than or equal to the number
of ports returned by GetRootHubPortNumber() , then EFI_INVALID_PARAMETER is
returned. Otherwise, the status of the USB root hub port is returned in PortStatus , and
EFI_SUCCESS is returned.
Status Codes Returned
EFI_SUCCESS The status of the USB root hub port specified by PortNumber
was returned in PortStatus .
EFI_INVALID_PARAMETER PortNumber is invalid.