On Sun, 30 Jun 2013, Ming Lei wrote: > > Come to think of it, we never should see an endpoint being disabled > > while there are active URBs. It might be a better idea to put a > > Right. > > > WARN_ON there and simply return, without unlinking anything. If this > > ever triggers, it means there's a bug in usbcore. > > But that isn't always true, see below case: > > - the last URB in the endpoint completes without resubmitting in its > completion handler > > - then the corresponding qh is kept in linked state, but wait for being unlinked > > - usb_disable_endpoint() is called before the qh is put into unlinked state, and > no URBs are unlinked in usb_hcd_flush_endpoint() > > - ehci_endpoint_disable() still see qh in QH_STATE_LINKED state. > > So I think we should unlink here to speed up the procedure as suggested > in your previous email. You are right. If the QH's qtd_list isn't empty then we should WARN_ON and return without doing anything -- just leak the QH. Otherwise, start the unlink immediately. (By the way, in your suggested patch, I would not define the eptype variable. Simply calculate the value where it is used. Also, you removed all usages of "tmp", so the declaration should be removed as well.) Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
