Intel Extensible Firmware Interface - Manual (Page 560)

Extensible Firmware Interface Specification
14-20 12/01/02 Version 1.10
DataToggle A pointer to the data toggle value. On input, it indicates the
initial data toggle value the synchronous interrupt transfer should
adopt; on output, it is updated to indicate the data toggle value of
the subsequent synchronous interrupt transfer.
TimeOut Indicates the maximum time, in milliseconds, which the transfer
is allowed to complete.
TransferResult A pointer to the detailed result information from the synchronous
interrupt transfer. Refer to Section 2.5.1 of EFI1.1 USB Driver
Model, version 0.7.
Description
This function is used to submit a synchronous interrupt transfer to a target endpoint of a USB
device. The target endpoint is specified by
DeviceAddress and EndpointAddress . In the
USB Specification, Revision 1.1, interrupt transfer is one of the four USB transfer types. In the
EFI_USB_HC_PROTOCOL , interrupt transfer is divided further into synchronous interrupt transfer
and asynchronous interrupt transfer.
The synchronous interrupt transfer is designed to retrieve small amounts of data from a USB device
through an interrupt endpoint. A synchronous interrupt transfer is only executed once for each
request. This is the most significant difference from the asynchronous interrupt transfer.
If the synchronous interrupt transfer is successful, then EFI_SUCCESS is returned. If the USB
transfer cannot be completed within the timeout specified by Timeout , then EFI_TIMEOUT is
returned. If an error other than timeout occurs during the USB transfer, then
EFI_DEVICE_ERROR is returned and the detailed status code is returned in TransferResult .
EFI_INVALID_PARAMETER is returned if one of the following conditions is satisfied:
1. Data transfer direction indicated by EndPointAddress is not EfiUsbDataIn .
2. Data is NULL .
3. DataLength is 0.
4. MaximumPacketLength is not valid. The legal value of this parameter is for the full-speed
device, it should be 8, 16, 32, or 64; for the slow device, it is limited to 8.
5. DataToggle points to a value other than 0 and 1.
6. TransferResult is NULL .
Status Codes Returned
EFI_SUCCESS The synchronous interrupt transfer was completed successfully.
EFI_OUT_OF_RESOURCES The synchronous interrupt transfer could not be submitted due to lack of
resource.
EFI_INVALID_PARAMETER Some parameters are invalid. The possible invalid parameters are
described in “Description” above.
EFI_TIMEOUT The synchronous interrupt transfer failed due to timeout.
EFI_DEVICE_ERROR The synchronous interrupt transfer failed due to host controller or device
error. Caller should check
TransferResult for detailed error
information.