usb: dwc3: gadget: always try to prepare on started_list first (d86c5a67) · Commits · 戴 / test

In cases where we're given an SG-list which is longer than the amount of currently available TRBs, we will be left with the same request on started_list and we should prioritize that request over possible new requests on pending_list. That's a way to guarantee requests complete in order. Signed-off-by:

Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/gadget.c

+18 −0

Original line number	Diff line number	Diff line
		@@ -1020,6 +1020,24 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep)
		if (!dwc3_calc_trbs_left(dep))
		return;

		/*
		* We can get in a situation where there's a request in the started list
		* but there weren't enough TRBs to fully kick it in the first time
		* around, so it has been waiting for more TRBs to be freed up.
		*
		* In that case, we should check if we have a request with pending_sgs
		* in the started list and prepare TRBs for that request first,
		* otherwise we will prepare TRBs completely out of order and that will
		* break things.
		*/
		list_for_each_entry(req, &dep->started_list, list) {
		if (req->num_pending_sgs > 0)
		dwc3_prepare_one_trb_sg(dep, req);

		if (!dwc3_calc_trbs_left(dep))
		return;
		}

		list_for_each_entry_safe(req, n, &dep->pending_list, list) {
		if (req->num_pending_sgs > 0)
		dwc3_prepare_one_trb_sg(dep, req);

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