Intel Extensible Firmware Interface - Manual (Page 544)

Extensible Firmware Interface Specification
14-4 12/01/02 Version 1.10
EFI_USB_HC_PROTOCOL.Reset()
Summary
Provides software reset for the USB host controller.
Prototype
typedef
EFI_STATUS
(EFIAPI *EFI_USB_HC_PROTOCOL_RESET) (
IN EFI_USB_HC_PROTOCOL
*This,
IN UINT16 Attributes
);
Parameters
This A pointer to the EFI_USB_HC_PROTOCOL instance. Type
EFI_USB_HC_PROTOCOL is defined in Section 14.1.
Attributes A bit mask of the reset operation to perform. See “Related
Definitions” below for a list of the supported bit mask values.
Related Definitions
#define EFI_USB_HC_RESET_GLOBAL 0x0001
#define EFI_USB_HC_RESET_HOST_CONTROLLER 0x0002
EFI_USB_HC_RESET_GLOBAL
If this bit is set, a global reset signal will be sent to the USB bus.
This resets all of the USB bus logic, including the USB host
controller hardware and all the devices attached on the USB bus.
EFI_USB_HC_RESET_HOST_CONTROLLER
If this bit is set, the USB host controller hardware will be reset.
No reset signal will be sent to the USB bus.
Description
This function provides a software mechanism to reset a USB host controller. The type of reset is
specified by the
Attributes parameter. If the type of reset specified by Attributes is not
valid, then EFI_INVALID_PARAMETER is returned. If the reset operation is completed, then
EFI_SUCCESS is returned. If the type of reset specified by Attributes is not currently
supported by the host controller hardware, EFI_UNSUPPORTD is returned. If a device error
occurs during the reset operation, then EFI_DEVICE_ERROR is returned.