3 files changed, 53 insertions, 15 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 25a7422ee657..8fb484984c86 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2324,12 +2324,16 @@ static unsigned hub_is_wusb(struct usb_hub *hub)
 static int hub_port_reset(struct usb_hub *hub, int port1,
                         struct usb_device *udev, unsigned int delay, bool warm);
 
-/* Is a USB 3.0 port in the Inactive state? */
-static bool hub_port_inactive(struct usb_hub *hub, u16 portstatus)
+/* Is a USB 3.0 port in the Inactive or Complinance Mode state?
+ * Port worm reset is required to recover
+ */
+static bool hub_port_warm_reset_required(struct usb_hub *hub, u16 portstatus)
 {
         return hub_is_superspeed(hub->hdev) &&
-                (portstatus & USB_PORT_STAT_LINK_STATE) ==
-                USB_SS_PORT_LS_SS_INACTIVE;
+                (((portstatus & USB_PORT_STAT_LINK_STATE) ==
+                  USB_SS_PORT_LS_SS_INACTIVE) ||
+                 ((portstatus & USB_PORT_STAT_LINK_STATE) ==
+                  USB_SS_PORT_LS_COMP_MOD)) ;
 }
 
 static int hub_port_wait_reset(struct usb_hub *hub, int port1,
@@ -2365,7 +2369,7 @@ static int hub_port_wait_reset(struct usb_hub *hub, int port1,
                          *
                          * See https://bugzilla.kernel.org/show_bug.cgi?id=41752
                          */
-                        if (hub_port_inactive(hub, portstatus)) {
+                        if (hub_port_warm_reset_required(hub, portstatus)) {
                                 int ret;
 
                                 if ((portchange & USB_PORT_STAT_C_CONNECTION))
@@ -4408,9 +4412,7 @@ static void hub_events(void)
                         /* Warm reset a USB3 protocol port if it's in
                          * SS.Inactive state.
                          */
-                        if (hub_is_superspeed(hub->hdev) &&
-                                (portstatus & USB_PORT_STAT_LINK_STATE)
-                                        == USB_SS_PORT_LS_SS_INACTIVE) {
+                        if (hub_port_warm_reset_required(hub, portstatus)) {
                                 dev_dbg(hub_dev, "warm reset port %d\n", i);
                                 hub_port_reset(hub, i, NULL,
                                                 HUB_BH_RESET_TIME, true);
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.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) */