[PATCH] USB: usbcore, hub driver enables TT-per-port mode

[USB] hub driver turns on multi-TT mode

This turns on the multi-tt mode in hubs that support it; the Cypress
"TetraHub" products are appearing at retail now, complete with some
of the first Mini-B connectors I've seen shipping.

This will be important for hooking up lots of full speed isochronous
devices (audio, video, etc).

drivers/usb/core/hub.c

@@ -405,9 +405,14 @@ static int hub_configure(struct usb_hub *hub,
 			hub->tt.hub = dev;
 			break;
 		case 2:
+			ret = usb_set_interface(dev, 0, 1);
+			if (ret == 0) {
 				dev_dbg(hub_dev, "TT per port\n");
-			hub->tt.hub = dev;
 				hub->tt.multi = 1;
+			} else
+				dev_err(hub_dev, "Using single TT (err %d)\n",
+					ret);
+			hub->tt.hub = dev;
 			break;
 		default:
 			dev_dbg(hub_dev, "Unrecognized hub protocol %d\n",