Intel Extensible Firmware Interface - Manual (Page 598)

Extensible Firmware Interface Specification
14-58 12/01/02 Version 1.10
Description
This function is used to retrieve the interface descriptor for the USB controller. If
InterfaceDescriptor is NULL , then EFI_INVALID_PARAMETER is returned. If the USB
controller does not contain an interface descriptor, then EFI_NOT_FOUND is returned. Otherwise,
the interface descriptor is returned in InterfaceDescriptor , and EFI_SUCCESS is returned.
Status Code Returned
EFI_SUCCESS The interface descriptor retrieved successfully.
EFI_INVALID_PARAMETER InterfaceDescriptor is NULL .
EFI_NOT_FOUND The interface descriptor cannot be found. The device may not be
correctly configured.