2.2.9.1.1 TS_URB_HEADER
Every TS_URB structure begins with a common header called TS_URB_HEADER.
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Size |
URB Function |
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RequestId |
A |
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Size (2 bytes): A 16-bit unsigned integer. The size in bytes of the TS_URB structure.
URB Function (2 bytes): A 16-bit unsigned integer. The URB function as specified in [MSFT-W2KDDK], Volume 2, Part 4, Chapter 3. The URB structure specified by the URB function is represented by appropriate TS_URB structure as it is described in this protocol.
RequestId (31 bits): A 31-bit field. An ID that uniquely identifies the TRANSFER_IN_REQUEST or TRANSFER_OUT_REQUEST.
A - NoAck (1 bit): A 1-bit field, this is the highest bit of a little endian byte-order field. If this bit is nonzero, the client is not to send a URB_COMPLETION message for this TRANSFER_OUT_REQUEST. This bit can be nonzero only if the NoAckIsochWriteJitterBufferSizeInMs field in USB_DEVICE_CAPABILITIES is nonzero and URB Function is set to URB_FUNCTION_ISOCH_TRANSFER. If the RequestId field is set to TRANSFER_IN_REQUEST, this field MUST be set to zero.