Intel Extensible Firmware Interface - Manual (Page 562)

Extensible Firmware Interface Specification
14-22 12/01/02 Version 1.10
Description
This function is used to submit isochronous transfer to a target endpoint of a USB device. The
target endpoint is specified by
DeviceAddress and EndpointAddress . Isochronous
transfers are used when working with isochronous date. It provides periodic, continuous
communication between the host and a device.
If the isochronous transfer is successful, then EFI_SUCCESS is returned. The isochronous
transfer is designed to be completed within one USB frame time, if it cannot be completed,
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 will be returned in
TransferResult .
EFI_INVALID_PARAMETER is returned if one of the following conditions is satisfied:
1. Data is NULL .
2. DataLength is 0.
3. MaximumPacketLength is larger than 1023.
4. TransferResul t is NULL .
Status Codes Returned
EFI_SUCCESS The isochronous transfer was completed successfully.
EFI_OUT_OF_RESOURCES The isochronous 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 isochronous transfer cannot be completed within the one USB
frame time.
EFI_DEVICE_ERROR The isochronous transfer failed due to host controller or device error.
Caller should check
TransferResult for detailed error information.