3 files changed, 54 insertions, 7 deletions

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 2732ef660c5c..7b01094d7993 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -462,6 +462,42 @@ void xhci_test_and_clear_bit(struct xhci_hcd *xhci, __le32 __iomem **port_array,
 	}
 }
 
+/* Updates Link Status for super Speed port */
+static void xhci_hub_report_link_state(u32 *status, u32 status_reg)
+{
+	u32 pls = status_reg & PORT_PLS_MASK;
+
+	/* resume state is a xHCI internal state.
+	 * Do not report it to usb core.
+	 */
+	if (pls == XDEV_RESUME)
+		return;
+
+	/* When the CAS bit is set then warm reset
+	 * should be performed on port
+	 */
+	if (status_reg & PORT_CAS) {
+		/* The CAS bit can be set while the port is
+		 * in any link state.
+		 * Only roothubs have CAS bit, so we
+		 * pretend to be in compliance mode
+		 * unless we're already in compliance
+		 * or the inactive state.
+		 */
+		if (pls != USB_SS_PORT_LS_COMP_MOD &&
+		    pls != USB_SS_PORT_LS_SS_INACTIVE) {
+			pls = USB_SS_PORT_LS_COMP_MOD;
+		}
+		/* Return also connection bit -
+		 * hub state machine resets port
+		 * when this bit is set.
+		 */
+		pls |= USB_PORT_STAT_CONNECTION;
+	}
+	/* update status field */
+	*status |= pls;
+}
+
 int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 		u16 wIndex, char *buf, u16 wLength)
 {
@@ -606,13 +642,9 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 			else
 				status |= USB_PORT_STAT_POWER;
 		}
-		/* Port Link State */
+		/* Update Port Link State for super speed ports*/
 		if (hcd->speed == HCD_USB3) {
-			/* resume state is a xHCI internal state.
-			 * Do not report it to usb core.
-			 */
-			if ((temp & PORT_PLS_MASK) != XDEV_RESUME)
-				status |= (temp & PORT_PLS_MASK);
+			xhci_hub_report_link_state(&status, temp);
 		}
 		if (bus_state->port_c_suspend & (1 << wIndex))
 			status |= 1 << USB_PORT_FEAT_C_SUSPEND;
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 23b4aefd1036..8275645889da 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -885,6 +885,17 @@ static void update_ring_for_set_deq_completion(struct xhci_hcd *xhci,
 	num_trbs_free_temp = ep_ring->num_trbs_free;
 	dequeue_temp = ep_ring->dequeue;
 
+	/* If we get two back-to-back stalls, and the first stalled transfer
+	 * ends just before a link TRB, the dequeue pointer will be left on
+	 * the link TRB by the code in the while loop.  So we have to update
+	 * the dequeue pointer one segment further, or we'll jump off
+	 * the segment into la-la-land.
+	 */
+	if (last_trb(xhci, ep_ring, ep_ring->deq_seg, ep_ring->dequeue)) {
+		ep_ring->deq_seg = ep_ring->deq_seg->next;
+		ep_ring->dequeue = ep_ring->deq_seg->trbs;
+	}
+
 	while (ep_ring->dequeue != dev->eps[ep_index].queued_deq_ptr) {
 		/* We have more usable TRBs */
 		ep_ring->num_trbs_free++;
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index de3d6e3e57be..55c0785810c9 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -341,7 +341,11 @@ struct xhci_op_regs {
 #define PORT_PLC	(1 << 22)
 /* port configure error change - port failed to configure its link partner */
 #define PORT_CEC	(1 << 23)
-/* bit 24 reserved */
+/* Cold Attach Status - xHC can set this bit to report device attached during
+ * Sx state. Warm port reset should be perfomed to clear this bit and move port
+ * to connected state.
+ */
+#define PORT_CAS	(1 << 24)
 /* wake on connect (enable) */
 #define PORT_WKCONN_E	(1 << 25)
 /* wake on disconnect (enable) */