Filter
Top Products
Extensible Firmware Interface Specification
14-52 12/01/02 Version 1.10
EFI_USB_IO_PROTOCOL.UsbAsyncIsochronousTransfer()
Summary
This function is used to manage a USB device with an isochronous transfer pipe. An asynchronous
Isochronous transfer is a nonblocking USB isochronous transfer.
Prototype
typedef
EFI_STATUS
(EFIAPI *EFI_USB_IO_ASYNC_ISOCHRONOUS_TRANSFER) (
IN EFI_USB_IO_PROTOCOL *This,
IN UINT8 DeviceEndpoint,
IN OUT VOID *Data,
IN UINTN DataLength,
IN EFI_ASYNC_USB_TRANSFER_CALLBACK IsochronousCallBack,
IN VOID *Context OPTIONAL
);
Parameters
This A pointer to the EFI_USB_IO_PROTOCOL instance. Type
EFI_USB_IO_PROTOCOL is defined in Section 14.2.5.
DeviceEndpoint The destination USB device endpoint to which the device request
is being sent. DeviceEndpoint must be between 0x01 and
0x0F or between 0x81 and 0x8F, otherwise
EFI_INVALID_PARAMETER is returned. If the endpoint is not
an ISOCHRONOUS endpoint, EFI_INVALID_PARAMETER is
returned. The MSB of this parameter indicates the endpoint
direction. The number “1” stands for an IN endpoint, and “0”
stands for an OUT endpoint.
Data A pointer to the buffer of data that will be transmitted to USB
device or received from USB device.
DataLength Specifies the length, in bytes, of the data to be sent to or received
from the USB device.
Context Data passed to the IsochronousCallback()
function. This
is an optional parameter and may be NULL.
IsochronousCallback The IsochronousCallback() function. This function is
called if the requested isochronous transfer is completed. See the
“Related Definitions” section of the
UsbAsyncInterruptTransfer()
function description.