include/linux/usb.h

1462  * @setup_packet: Only used for control transfers, this points to eight bytes
1466  *	this field; setup_packet must point to a valid buffer.
1492  * (control requests also use setup_packet), and host controller drivers
1513  * The setup_packet must always be set, so it cannot be located in highmem.
1528  * Control URBs must provide a valid pointer in the setup_packet field.
1529  * Unlike the transfer_buffer, the setup_packet may not be mapped for DMA
1619 	unsigned char *setup_packet;	/* (in) setup packet (control only) */
1620 	dma_addr_t setup_dma;		/* (in) dma addr for setup_packet */
1639  * @setup_packet: pointer to the setup_packet buffer. The buffer must be
1650  * The transfer buffer and the setup_packet buffer will most likely be filled
1662 					unsigned char *setup_packet,
1670 	urb->setup_packet = setup_packet;