USB: xhci: Handle babbling endpoints correctly.

The 0.95 xHCI spec says that non-control endpoints will be halted if a
babble is detected on a transfer. The 0.96 xHCI spec says all types of
endpoints will be halted when a babble is detected. Some hardware that
claims to be 0.95 compliant halts the control endpoint anyway.

When a babble is detected on a control endpoint, check the hardware's
output endpoint context to see if the endpoint is marked as halted. If
the control endpoint is halted, a reset endpoint command must be issued
and the transfer ring dequeue pointer needs to be moved past the stopped
transfer. Basically, we treat it as if the control endpoint had stalled.

Handle bulk babbling endpoints as if we got a completion event with a
stall completion code.

Signed-off-by: Sarah Sharp <[e-mail]>
Cc: stable <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/xhci-ring.c

···
 			xhci_warn(xhci, "WARN: short transfer on control ep\n");
 			status = -EREMOTEIO;
 			break;
+		case COMP_BABBLE:
+			/* The 0.96 spec says a babbling control endpoint
+			 * is not halted. The 0.96 spec says it is.  Some HW
+			 * claims to be 0.95 compliant, but it halts the control
+			 * endpoint anyway.  Check if a babble halted the
+			 * endpoint.
+			 */
+			if (ep_ctx->ep_info != EP_STATE_HALTED)
+				break;
+			/* else fall through */
 		case COMP_STALL:
 			/* Did we transfer part of the data (middle) phase? */
 			if (event_trb != ep_ring->dequeue &&
···
 		ep_ring->stopped_td = td;
 		ep_ring->stopped_trb = event_trb;
 	} else {
-		if (GET_COMP_CODE(event->transfer_len) == COMP_STALL) {
+		if (trb_comp_code == COMP_STALL ||
+				trb_comp_code == COMP_BABBLE) {
 			/* The transfer is completed from the driver's
 			 * perspective, but we need to issue a set dequeue
 			 * command for this stalled endpoint to move the dequeue
···
 		 * control endpoints).
 		 */
 		if (usb_endpoint_xfer_control(&urb->ep->desc) ||
-			GET_COMP_CODE(event->transfer_len) != COMP_STALL) {
+			(trb_comp_code != COMP_STALL &&
+				trb_comp_code != COMP_BABBLE)) {
 			kfree(td);
 		}
 		urb->hcpriv = NULL;