2 files changed, 34 insertions, 8 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 4191db32f12c..c857471519e3 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2848,6 +2848,15 @@ static int usb_disable_function_remotewakeup(struct usb_device *udev)
                                 USB_CTRL_SET_TIMEOUT);
 }
 
+/* Count of wakeup-enabled devices at or below udev */
+static unsigned wakeup_enabled_descendants(struct usb_device *udev)
+{
+        struct usb_hub *hub = usb_hub_to_struct_hub(udev);
+
+        return udev->do_remote_wakeup +
+                        (hub ? hub->wakeup_enabled_descendants : 0);
+}
+
 /*
  * usb_port_suspend - suspend a usb device's upstream port
  * @udev: device that's no longer in active use, not a root hub
@@ -2888,8 +2897,8 @@ static int usb_disable_function_remotewakeup(struct usb_device *udev)
  * Linux (2.6) currently has NO mechanisms to initiate that:  no khubd
  * timer, no SRP, no requests through sysfs.
  *
- * If Runtime PM isn't enabled or used, non-SuperSpeed devices really get
- * suspended only when their bus goes into global suspend (i.e., the root
+ * If Runtime PM isn't enabled or used, non-SuperSpeed devices may not get
+ * suspended until their bus goes into global suspend (i.e., the root
  * hub is suspended).  Nevertheless, we change @udev->state to
  * USB_STATE_SUSPENDED as this is the device's "logical" state.  The actual
  * upstream port setting is stored in @udev->port_is_suspended.
@@ -2960,15 +2969,21 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
         /* see 7.1.7.6 */
         if (hub_is_superspeed(hub->hdev))
                 status = hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_U3);
-        else if (PMSG_IS_AUTO(msg))
-                status = set_port_feature(hub->hdev, port1,
-                                                USB_PORT_FEAT_SUSPEND);
+
         /*
          * For system suspend, we do not need to enable the suspend feature
          * on individual USB-2 ports.  The devices will automatically go
          * into suspend a few ms after the root hub stops sending packets.
          * The USB 2.0 spec calls this "global suspend".
+         *
+         * However, many USB hubs have a bug: They don't relay wakeup requests
+         * from a downstream port if the port's suspend feature isn't on.
+         * Therefore we will turn on the suspend feature if udev or any of its
+         * descendants is enabled for remote wakeup.
          */
+        else if (PMSG_IS_AUTO(msg) || wakeup_enabled_descendants(udev) > 0)
+                status = set_port_feature(hub->hdev, port1,
+                                USB_PORT_FEAT_SUSPEND);
         else {
                 really_suspend = false;
                 status = 0;
@@ -3003,15 +3018,16 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
                 if (!PMSG_IS_AUTO(msg))
                         status = 0;
         } else {
-                /* device has up to 10 msec to fully suspend */
                 dev_dbg(&udev->dev, "usb %ssuspend, wakeup %d\n",
                                 (PMSG_IS_AUTO(msg) ? "auto-" : ""),
                                 udev->do_remote_wakeup);
-                usb_set_device_state(udev, USB_STATE_SUSPENDED);
                 if (really_suspend) {
                         udev->port_is_suspended = 1;
+
+                        /* device has up to 10 msec to fully suspend */
                         msleep(10);
                 }
+                usb_set_device_state(udev, USB_STATE_SUSPENDED);
         }
 
         /*
@@ -3293,7 +3309,11 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
         unsigned                port1;
         int                     status;
 
-        /* Warn if children aren't already suspended */
+        /*
+         * Warn if children aren't already suspended.
+         * Also, add up the number of wakeup-enabled descendants.
+         */
+        hub->wakeup_enabled_descendants = 0;
         for (port1 = 1; port1 <= hdev->maxchild; port1++) {
                 struct usb_device       *udev;
 
@@ -3303,6 +3323,9 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
                         if (PMSG_IS_AUTO(msg))
                                 return -EBUSY;
                 }
+                if (udev)
+                        hub->wakeup_enabled_descendants +=
+                                        wakeup_enabled_descendants(udev);
         }
 
         if (hdev->do_remote_wakeup && hub->quirk_check_port_auto_suspend) {
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 6508e02b3dac..4e4790dea343 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -59,6 +59,9 @@ struct usb_hub {
         struct usb_tt           tt;             /* Transaction Translator */
 
         unsigned                mA_per_port;    /* current for each child */
+#ifdef  CONFIG_PM
+        unsigned                wakeup_enabled_descendants;
+#endif
 
         unsigned                limited_power:1;
         unsigned                quiescing:1;