[PATCH] USB ehci: handle earlier endpoint_disable()

The recent patch to scrub out ep0 state earlier (to get rid of some of
the enumeration problems that started with about 2.6.6) requires EHCI
to handle endpoint_disable() calls in a slightly different context.

This makes those calls work when an endpoint's QH may still be on the
async schedule, rather than already unlinked.  (The QH stays on the async
schedule for a few milliseconds after it's empty, since it's routine to
issue another request almost immediately.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/usb/host/ehci-hcd.c

@@ -862,6 +862,30 @@ static int ehci_urb_enqueue (
 	}
 }
 
+static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
+{
+	/* if we need to use IAA and it's busy, defer */
+	if (qh->qh_state == QH_STATE_LINKED
+			&& ehci->reclaim
+			&& HCD_IS_RUNNING (ehci->hcd.state)) {
+		struct ehci_qh		*last;
+
+		for (last = ehci->reclaim;
+				last->reclaim;
+				last = last->reclaim)
+			continue;
+		qh->qh_state = QH_STATE_UNLINK_WAIT;
+		last->reclaim = qh;
+
+	/* bypass IAA if the hc can't care */
+	} else if (!HCD_IS_RUNNING (ehci->hcd.state) && ehci->reclaim)
+		end_unlink_async (ehci, NULL);
+
+	/* something else might have unlinked the qh by now */
+	if (qh->qh_state == QH_STATE_LINKED)
+		start_unlink_async (ehci, qh);
+}
+
 /* remove from hardware lists
  * completions normally happen asynchronously
  */
@@ -880,28 +904,7 @@ static int ehci_urb_dequeue (struct usb_hcd *hcd, struct urb *urb)
 		qh = (struct ehci_qh *) urb->hcpriv;
 		if (!qh)
 			break;
-
-		/* if we need to use IAA and it's busy, defer */
-		if (qh->qh_state == QH_STATE_LINKED
-				&& ehci->reclaim
-				&& HCD_IS_RUNNING (ehci->hcd.state)
-				) {
-			struct ehci_qh		*last;
-
-			for (last = ehci->reclaim;
-					last->reclaim;
-					last = last->reclaim)
-				continue;
-			qh->qh_state = QH_STATE_UNLINK_WAIT;
-			last->reclaim = qh;
-
-		/* bypass IAA if the hc can't care */
-		} else if (!HCD_IS_RUNNING (ehci->hcd.state) && ehci->reclaim)
-			end_unlink_async (ehci, NULL);
-
-		/* something else might have unlinked the qh by now */
-		if (qh->qh_state == QH_STATE_LINKED)
-			start_unlink_async (ehci, qh);
+		unlink_async (ehci, qh);
 		break;
 
 	case PIPE_INTERRUPT:
@@ -954,7 +957,7 @@ ehci_endpoint_disable (struct usb_hcd *hcd, struct hcd_dev *dev, int ep)
 	struct ehci_hcd		*ehci = hcd_to_ehci (hcd);
 	int			epnum;
 	unsigned long		flags;
-	struct ehci_qh		*qh;
+	struct ehci_qh		*qh, *tmp;
 
 	/* ASSERT:  any requests/urbs are being unlinked */
 	/* ASSERT:  nobody can be submitting urbs for this any more */
@@ -980,6 +983,16 @@ ehci_endpoint_disable (struct usb_hcd *hcd, struct hcd_dev *dev, int ep)
 	if (!HCD_IS_RUNNING (ehci->hcd.state))
 		qh->qh_state = QH_STATE_IDLE;
 	switch (qh->qh_state) {
+	case QH_STATE_LINKED:
+		for (tmp = ehci->async->qh_next.qh;
+				tmp && tmp != qh;
+				tmp = tmp->qh_next.qh)
+			continue;
+		/* periodic qh self-unlinks on empty */
+		if (!tmp)
+			goto nogood;
+		unlink_async (ehci, qh);
+		/* FALL THROUGH */
 	case QH_STATE_UNLINK:		/* wait for hw to finish? */
 idle_timeout:
 		spin_unlock_irqrestore (&ehci->lock, flags);
@@ -993,6 +1006,7 @@ ehci_endpoint_disable (struct usb_hcd *hcd, struct hcd_dev *dev, int ep)
 		}
 		/* else FALL THROUGH */
 	default:
+nogood:
 		/* caller was supposed to have unlinked any requests;
 		 * that's not our job.  just leak this memory.
 		 */