USB_LOOKUP_EP_DATA(9F) Kernel Functions for Drivers USB_LOOKUP_EP_DATA(9F)

usb_lookup_ep_data - Lookup endpoint information

#include <sys/usb/usba.h>
usb_ep_data_t *usb_lookup_ep_data(dev_info_t *dip,
     usb_client_dev_data_t *dev_datap, uint_t interface,
     uint_t alternate, uint_t skip, uint_t type, uint_t direction);

illumos DDI specific (illumos DDI)

Pointer to the device's dev_info structure.


Pointer to a usb_client_dev_data_t structure containing tree.


Number of interface in which endpoint resides.


Number of interface alternate setting in which endpoint resides.


Number of endpoints which match the requested type and direction to skip before finding one to retrieve.


Type of endpoint. This is one of: USB_EP_ATTR_CONTROL, USB_EP_ATTR_ISOCH, USB_EP_ATTR_BULK, or USB_EP_ATTR_INTR. Please see usb_pipe_xopen(9F) for more information.


Direction of endpoint, either USB_EP_DIR_OUT or USB_EP_DIR_IN. This argument is ignored for bi-directional control endpoints.

The usb_lookup_ep_data() function returns endpoint information from the tree embedded in client data returned from usb_get_dev_data. It operates on the current configuration (pointed to by the dev_curr_cfg field of the usb_client_dev_data_t argument). It skips the first <skip> number of endpoints it finds which match the specifications of the other arguments, and then retrieves information on the next matching endpoint it finds. Note that it does not make a copy of the data, but points to the tree itself.

On success: the tree node corresponding to the desired endpoint.

On failure: returns NULL. Fails if dip or dev_datap are NULL, if the desired endpoint does not exist in the tree, or no tree is present in dev_datap.

May be called from user, kernel or interrupt context.

Retrieve the polling interval for the second interrupt endpoint at interface 0, alt 3:

    uint8_t interval = 0;
    usb_ep_data_t *ep_node = usb_lookup_ep_data(
        dip, dev_datap, 0, 3, 1, USB_EP_ATTR_INTR, USB_EP_DIR_IN);
    if (ep_node != NULL) {
            interval = ep_node->ep_descr.bInterval;

Retrieve the maximum packet size for the first control pipe at interface 0, alt 4:

    uint16_t maxPacketSize = 0;
    usb_ep_data_t *ep_node = usb_lookup_ep_data(
        dip, dev_datap, 0, 4, 0, USB_EP_ATTR_CONTROL, 0);
    if (ep_node != NULL) {
            maxPacketSize = ep_node->ep_descr.wMaxPacketSize;

See attributes(5) for descriptions of the following attributes:

Architecture PCI-based systems
Interface stability Committed

attributes(5), usb_get_dev_data(9F), usb_pipe_open(9F), usb_cfg_descr(9S), usb_if_descr(9S), usb_ep_descr(9S)
September 16, 2016 OmniOS