USB_CTRL_REQUEST(9S) Data Structures for Drivers USB_CTRL_REQUEST(9S)


usb_ctrl_req, usb_ctrl_req_t, usb_ctrl_request - USB control pipe request


#include <sys/usb/usba.h>


illumos DDI specific (illumos DDI)


A control request is used to send device commands (or requests) and to
read status. Please refer to Section 5.5 of the USB 2.0 specification for
information on control pipes. For information on formatting requests, see
Section 9.3 of the USB 2.0 specification. The USB 2.0 specification is
available at


The fields in the usb_ctrl_req_t are used to format a control request:

uint8_t ctrl_bmRequestType; /* characteristics of request */
uint8_t ctrl_bRequest; /* specific request */
uint16_t ctrl_wValue; /* varies according to request */
uint16_t ctrl_wIndex; /* index or offset */
uint16_t ctrl_wLength; /* number of bytes to xfer */
mblk_t *ctrl_data; /* data for the data phase */
/* IN or OUT: allocated by client */
uint_t ctrl_timeout; /* time until USBA framework */
/* retires req, in seconds */
/* If set to zero, defaults to 5 sec */
usb_opaque_t ctrl_client_private; /* client private info */
usb_req_attrs_t ctrl_attributes; /* attrib. for this req */

/* Normal callback function, called upon completion. */
void (*ctrl_cb)(
usb_pipe_handle_t ph, struct usb_ctrl_req *req);

/* Exception callback function, for error handling. */
void (*ctrl_exc_cb)(
usb_pipe_handle_t ph, struct usb_ctrl_req *req);
usb_cr_t ctrl_completion_reason; /* overall success status */
/* See usb_completion_reason(9S) */
usb_cb_flags_t ctrl_cb_flags; /* recovery done by callback hndlr */
/* See usb_callback_flags(9S) */

Request attributes define special handling for transfers. The following
attributes are valid for control requests:

Accept transfers where less data is received
than expected.

Have USB framework reset pipe and clear
functional stalls automatically on exception.

Have USB framework reset pipe automatically on

Please see usb_request_attributes(9S) for more information.

The following definitions directly pertain to fields in the USB control
request structure. (See Section 9.3 of the USB 2.0 specification.)

Direction bitmasks of a control request's ctrl_bmRequestType field
(USB 2.0 spec, section 9.3.1)

USB_DEV_REQ_HOST_TO_DEV | Host to device direction
USB_DEV_REQ_DEV_TO_HOST | Device to host direction
USB_DEV_REQ_DIR_MASK | Bitmask of direction bits

Request type bitmasks of a control request's ctrl_bmRequestType field
(USB 2.0 spec, section 9.3.1)

USB_DEV_REQ_TYPE_STANDARD | USB 2.0 defined command
| for all USB devices
| class-specific command
USB_DEV_REQ_TYPE_VENDOR | Vendor-specific command
USB_DEV_REQ_TYPE_MASK | Bitmask of request type bits

Recipient bitmasks of a control request's ctrl_bmRequestType field
(USB 2.0 spec, section 9.3.1)

USB_DEV_REQ_RCPT_DEV | Request is for device
USB_DEV_REQ_RCPT_IF | Request is for interface
USB_DEV_REQ_RCPT_EP | Request is for endpoint
USB_DEV_REQ_RCPT_OTHER | Req is for other than above
USB_DEV_REQ_RCPT_MASK | Bitmask of request recipient bits

Standard requests (USB 2.0 spec, section 9.4)
USB_REQ_GET_STATUS | Get status of device, endpoint
|or interface (9.4.5)
USB_REQ_CLEAR_FEATURE | Clear feature specified by
|wValue field (9.4.1)
USB_REQ_SET_FEATURE | Set feature specified by
| wValue field (9.4.9)
USB_REQ_SET_ADDRESS | Set address specified by
| wValue field (9.4.6)
USB_REQ_GET_DESCR | Get descr for item/idx in
| wValue field (9.4.3)
USB_REQ_SET_DESCR | Set descr for item/idx in
| wValue field (9.4.8)
USB_REQ_GET_CFG | Get current device
| configuration (9.4.2)
USB_REQ_SET_CFG | Set current device
| configuration (9.4.7)
USB_REQ_GET_IF | Get alternate interface
| setting (9.4.4)
USB_REQ_SET_IF | Set alternate interface
| setting (9.4.10)
USB_REQ_SYNC_FRAME | Set and report an endpoint's
| sync frame (9.4.11)

Unicode language ID, used as wIndex for USB_REQ_SET/GET_DESCRIPTOR

USB_LANG_ID | Unicode English Lang ID for
| parsing str descr


See attributes(7) for descriptions of the following attributes:

|Architecture | PCI-based systems |
|Interface stability | Committed |


usb_alloc_request(9F), usb_pipe_bulk_xfer(9F), usb_pipe_ctrl_xfer(9F),
usb_pipe_intr_xfer(9F), usb_pipe_isoc_xfer(9F), usb_bulk_request(9S),
usb_callback_flags(9S), usb_completion_reason(9S), usb_intr_request(9S),
usb_isoc_request(9S), usb_request_attributes(9S)

illumos January 5, 2004 USB_CTRL_REQUEST(9S)