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Commit d889c23c authored by Felipe Balbi's avatar Felipe Balbi
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usb: dwc3: gadget: never pre-start Isochronous endpoints 



We cannot pre-start isochronous endpoints because we
rely on the micro-frame number passed via
XferNotReady command for proper Isochronous
scheduling.

Fixes: 08a36b54 ("usb: dwc3: gadget: simplify __dwc3_gadget_ep_queue()")
Signed-off-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
parent a9c3ca5f

drivers/usb/dwc3/gadget.c

+11 −3
Original line number Diff line number Diff line
@@ -1073,9 +1073,17 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req) 


	list_add_tail(&req->list, &dep->pending_list);



	if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&

			dep->flags & DWC3_EP_PENDING_REQUEST) {

		if (list_empty(&dep->started_list)) {

	/*

	 * NOTICE: Isochronous endpoints should NEVER be prestarted. We must

	 * wait for a XferNotReady event so we will know what's the current

	 * (micro-)frame number.

	 *

	 * Without this trick, we are very, very likely gonna get Bus Expiry

	 * errors which will force us issue EndTransfer command.

	 */

	if (usb_endpoint_xfer_isoc(dep->endpoint.desc)) {

		if ((dep->flags & DWC3_EP_PENDING_REQUEST) &&

				list_empty(&dep->started_list)) {

			dwc3_stop_active_transfer(dwc, dep->number, true);

			dep->flags = DWC3_EP_ENABLED;

		}