UsbRtDxe

USB Runtime DXE driver -- the largest USB module in the Lenovo HR650X BIOS with approximately 265 functions. This is a comprehensive USB driver stack that provides USB host controller management at the DXE and runtime phases. It implements USB bus driver functionality including device enumeration, transfer management (control, bulk, interrupt, isochronous), hub management, and USB descriptor parsing. The driver supports both EHCI (USB 2.0) and xHCI (USB 3.0) controller interfaces and maintains runtime services for OS-visible USB data after ExitBootServices.

Key Functions

• ModuleEntryPoint -- Standard UEFI entry point
• UsbDriverEntryPoint -- USB bus driver main entry; installs driver binding protocol
• UsbHubInit -- USB hub initialization and port enumeration
• UsbDeviceConnect -- USB device connect/disconnect state machine
• UsbTransferControl/Bulk/Interrupt/Isochronous -- Transfer type dispatchers
• UsbDescriptorParse -- USB descriptor parsing (device, config, interface, endpoint)

Dependencies

• UefiBootServicesTableLib, UefiRuntimeServicesTableLib
• DebugLib, BaseLib, MemoryAllocationLib
• USB Bus Driver Binding Protocol, EHCI/xHCI host controller protocols
• TimerLib, UefiUsbLib

Platform

x86-64 PE32+ (UEFI DXE driver), Lenovo HR650X (Purley/Intel grantley-EP), AMI ModulePkg