Implement better error recovery for Transaction Translators, TTs,

found in High Speed USB HUBs which translate from High Speed USB into
FULL or LOW speed USB. In some rare cases SPLIT transactions might get
lost, which might leave the TT in an unknown state. Whenever we detect
such an error try to issue either a clear TT buffer request, or if
that is not possible reset the whole TT.

MFC after:	1 week

1 files changed, 24 insertions, 3 deletions

diff --git a/sys/dev/usb/usb_request.c b/sys/dev/usb/usb_request.c
index cecc167..8c92715 100644
--- a/sys/dev/usb/usb_request.c
+++ b/sys/dev/usb/usb_request.c
@@ -721,6 +721,17 @@ done:
 	if ((mtx != NULL) && (mtx != &Giant))
 		mtx_lock(mtx);
 
+	switch (err) {
+	case USB_ERR_NORMAL_COMPLETION:
+	case USB_ERR_SHORT_XFER:
+	case USB_ERR_STALLED:
+	case USB_ERR_CANCELLED:
+		break;
+	default:
+		DPRINTF("I/O error - waiting a bit for TT cleanup\n");
+		usb_pause_mtx(mtx, hz / 16);
+		break;
+	}
 	return ((usb_error_t)err);
 }
 
@@ -2010,6 +2021,7 @@ usbd_req_re_enumerate(struct usb_device *udev, struct mtx *mtx)
 		return (USB_ERR_INVAL);
 	}
 retry:
+#if USB_HAVE_TT_SUPPORT
 	/*
 	 * Try to reset the High Speed parent HUB of a LOW- or FULL-
 	 * speed device, if any.
@@ -2017,15 +2029,24 @@ retry:
 	if (udev->parent_hs_hub != NULL &&
 	    udev->speed != USB_SPEED_HIGH) {
 		DPRINTF("Trying to reset parent High Speed TT.\n");
-		err = usbd_req_reset_tt(udev->parent_hs_hub, NULL,
-		    udev->hs_port_no);
+		if (udev->parent_hs_hub == parent_hub &&
+		    (uhub_count_active_host_ports(parent_hub, USB_SPEED_LOW) +
+		     uhub_count_active_host_ports(parent_hub, USB_SPEED_FULL)) == 1) {
+			/* we can reset the whole TT */
+			err = usbd_req_reset_tt(parent_hub, NULL,
+			    udev->hs_port_no);
+		} else {
+			/* only reset a particular device and endpoint */
+			err = usbd_req_clear_tt_buffer(udev->parent_hs_hub, NULL,
+			    udev->hs_port_no, old_addr, UE_CONTROL, 0);
+		}
 		if (err) {
 			DPRINTF("Resetting parent High "
 			    "Speed TT failed (%s).\n",
 			    usbd_errstr(err));
 		}
 	}
-
+#endif
 	/* Try to warm reset first */
 	if (parent_hub->speed == USB_SPEED_SUPER)
 		usbd_req_warm_reset_port(parent_hub, mtx, udev->port_no);