---

yaml
---
r: 361254
b: refs/heads/master
c: 6402c79
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ea5301aa130a07e8d0f8bd7d7d3124f45e592208
+refs/heads/master: 6402c796d3b4205d3d7296157956c5100a05d7d6

trunk/drivers/usb/host/ehci-hcd.c

@@ -748,11 +748,9 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
 		/* guard against (alleged) silicon errata */
 		if (cmd & CMD_IAAD)
 			ehci_dbg(ehci, "IAA with IAAD still set?\n");
-		if (ehci->async_iaa) {
+		if (ehci->async_iaa)
 			COUNT(ehci->stats.iaa);
-			end_unlink_async(ehci);
-		} else
-			ehci_dbg(ehci, "IAA with nothing unlinked?\n");
+		end_unlink_async(ehci);
 	}
 
 	/* remote wakeup [4.3.1] */

trunk/drivers/usb/host/ehci-q.c

@@ -1170,7 +1170,7 @@ static void single_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh)
 	struct ehci_qh		*prev;
 
 	/* Add to the end of the list of QHs waiting for the next IAAD */
-	qh->qh_state = QH_STATE_UNLINK;
+	qh->qh_state = QH_STATE_UNLINK_WAIT;
 	if (ehci->async_unlink)
 		ehci->async_unlink_last->unlink_next = qh;
 	else
@@ -1213,9 +1213,19 @@ static void start_iaa_cycle(struct ehci_hcd *ehci, bool nested)
 
 		/* Do only the first waiting QH (nVidia bug?) */
 		qh = ehci->async_unlink;
-		ehci->async_iaa = qh;
-		ehci->async_unlink = qh->unlink_next;
-		qh->unlink_next = NULL;
+
+		/*
+		 * Intel (?) bug: The HC can write back the overlay region
+		 * even after the IAA interrupt occurs.  In self-defense,
+		 * always go through two IAA cycles for each QH.
+		 */
+		if (qh->qh_state == QH_STATE_UNLINK_WAIT) {
+			qh->qh_state = QH_STATE_UNLINK;
+		} else {
+			ehci->async_iaa = qh;
+			ehci->async_unlink = qh->unlink_next;
+			qh->unlink_next = NULL;
+		}
 
 		/* Make sure the unlinks are all visible to the hardware */
 		wmb();