Man page 9 : usb_ep_dequeue

usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint

int usb_ep_dequeue(struct usb_ep *  ep , struct usb_request *  req );

ep
    the endpoint associated with the request

req
    the request being canceled

if the request is still active on the endpoint, it is dequeued and its completion routine is called (with status -ECONNRESET); else a negative error code is returned.

note that some hardware canAqt clear out write fifos (to unlink the request at the head of the queue) except as part of disconnecting from usb. such restrictions prevent drivers from supporting configuration changes, even to configuration zero (a « chapter 9 » requirement).

David Brownell <>
    Author.