4 files changed, 60 insertions, 10 deletions

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index ccf0a06199a3..773a6b28c4f1 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -552,11 +552,15 @@ void xhci_del_comp_mod_timer(struct xhci_hcd *xhci, u32 status, u16 wIndex)
  *  - Mark a port as being done with device resume,
  *    and ring the endpoint doorbells.
  *  - Stop the Synopsys redriver Compliance Mode polling.
+ *  - Drop and reacquire the xHCI lock, in order to wait for port resume.
  */
 static u32 xhci_get_port_status(struct usb_hcd *hcd,
 		struct xhci_bus_state *bus_state,
 		__le32 __iomem **port_array,
-		u16 wIndex, u32 raw_port_status)
+		u16 wIndex, u32 raw_port_status,
+		unsigned long flags)
+	__releases(&xhci->lock)
+	__acquires(&xhci->lock)
 {
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 	u32 status = 0;
@@ -591,21 +595,42 @@ static u32 xhci_get_port_status(struct usb_hcd *hcd,
 			return 0xffffffff;
 		if (time_after_eq(jiffies,
 					bus_state->resume_done[wIndex])) {
+			int time_left;
+
 			xhci_dbg(xhci, "Resume USB2 port %d\n",
 					wIndex + 1);
 			bus_state->resume_done[wIndex] = 0;
 			clear_bit(wIndex, &bus_state->resuming_ports);
+
+			set_bit(wIndex, &bus_state->rexit_ports);
 			xhci_set_link_state(xhci, port_array, wIndex,
 					XDEV_U0);
-			xhci_dbg(xhci, "set port %d resume\n",
-					wIndex + 1);
-			slot_id = xhci_find_slot_id_by_port(hcd, xhci,
-					wIndex + 1);
-			if (!slot_id) {
-				xhci_dbg(xhci, "slot_id is zero\n");
-				return 0xffffffff;
+
+			spin_unlock_irqrestore(&xhci->lock, flags);
+			time_left = wait_for_completion_timeout(
+					&bus_state->rexit_done[wIndex],
+					msecs_to_jiffies(
+						XHCI_MAX_REXIT_TIMEOUT));
+			spin_lock_irqsave(&xhci->lock, flags);
+
+			if (time_left) {
+				slot_id = xhci_find_slot_id_by_port(hcd,
+						xhci, wIndex + 1);
+				if (!slot_id) {
+					xhci_dbg(xhci, "slot_id is zero\n");
+					return 0xffffffff;
+				}
+				xhci_ring_device(xhci, slot_id);
+			} else {
+				int port_status = xhci_readl(xhci,
+						port_array[wIndex]);
+				xhci_warn(xhci, "Port resume took longer than %i msec, port status = 0x%x\n",
+						XHCI_MAX_REXIT_TIMEOUT,
+						port_status);
+				status |= USB_PORT_STAT_SUSPEND;
+				clear_bit(wIndex, &bus_state->rexit_ports);
 			}
-			xhci_ring_device(xhci, slot_id);
+
 			bus_state->port_c_suspend |= 1 << wIndex;
 			bus_state->suspended_ports &= ~(1 << wIndex);
 		} else {
@@ -728,7 +753,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 			break;
 		}
 		status = xhci_get_port_status(hcd, bus_state, port_array,
-				wIndex, temp);
+				wIndex, temp, flags);
 		if (status == 0xffffffff)
 			goto error;
 
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 53b972c2a09f..83bcd13622c3 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2428,6 +2428,8 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	for (i = 0; i < USB_MAXCHILDREN; ++i) {
 		xhci->bus_state[0].resume_done[i] = 0;
 		xhci->bus_state[1].resume_done[i] = 0;
+		/* Only the USB 2.0 completions will ever be used. */
+		init_completion(&xhci->bus_state[1].rexit_done[i]);
 	}
 
 	if (scratchpad_alloc(xhci, flags))
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 9ac9672d4498..dd02402700d5 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1759,6 +1759,19 @@ static void handle_port_status(struct xhci_hcd *xhci,
 		}
 	}
 
+	/*
+	 * Check to see if xhci-hub.c is waiting on RExit to U0 transition (or
+	 * RExit to a disconnect state).  If so, let the the driver know it's
+	 * out of the RExit state.
+	 */
+	if (!DEV_SUPERSPEED(temp) &&
+			test_and_clear_bit(faked_port_index,
+				&bus_state->rexit_ports)) {
+		complete(&bus_state->rexit_done[faked_port_index]);
+		bogus_port_status = true;
+		goto cleanup;
+	}
+
 	if (hcd->speed != HCD_USB3)
 		xhci_test_and_clear_bit(xhci, port_array, faked_port_index,
 					PORT_PLC);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index f3e10206cd95..289fbfbae746 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1412,8 +1412,18 @@ struct xhci_bus_state {
 	unsigned long		resume_done[USB_MAXCHILDREN];
 	/* which ports have started to resume */
 	unsigned long		resuming_ports;
+	/* Which ports are waiting on RExit to U0 transition. */
+	unsigned long		rexit_ports;
+	struct completion	rexit_done[USB_MAXCHILDREN];
 };
 
+
+/*
+ * It can take up to 20 ms to transition from RExit to U0 on the
+ * Intel Lynx Point LP xHCI host.
+ */
+#define	XHCI_MAX_REXIT_TIMEOUT	(20 * 1000)
+
 static inline unsigned int hcd_index(struct usb_hcd *hcd)
 {
 	if (hcd->speed == HCD_USB3)