Intel Extensible Firmware Interface - Manual (Page 593)

Protocols — USB Support
Version 1.10 12/01/02 14-53
Description
This is an asynchronous type of USB isochronous transfer. If the caller submits a USB isochronous
transfer request through this function, this function will return immediately. When the isochronous
transfer completes, the
IsochronousCallback() function will be triggered, the caller can
know the transfer results. If the transfer is successful, the caller can get the data received or sent in
this callback function.
Status Code Returned
EFI_SUCCESS The asynchronous isochronous transfer has been successfully submitted
to the system.
EFI_INVALID_PARAMETER The parameter DeviceEndpoint is not valid.
EFI_OUT_OF_RESOURCES The request could not be submitted due to a lack of resources.