USB: handle LPM errors during device suspend correctly

The hub driver's usb_port_suspend() routine doesn't handle errors
related to Link Power Management properly.  It always returns failure,
it doesn't try to clean up the wakeup setting, (in the case of system
sleep) it doesn't try to go ahead with the port suspend regardless,
and it doesn't try to apply the new power-off mechanism.

This patch fixes these problems.

Note: Sarah fixed this patch to apply against 3.11, since the original
commit (4fae6f0fa86f92e6bc7429371b1e177ad0aaac66 "USB: handle LPM errors
during device suspend correctly") called usb_disable_remote_wakeup,
which won't be added until 3.12.

This patch should be backported to kernels as old as 3.5, that
contain the commit 8306095fd2c1100e8244c09bf560f97aca5a311d "USB:
Disable USB 3.0 LPM in critical sections.".  There will be merge
conflicts, since LTM wasn't added until 3.6.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org

drivers/usb/core/hub.c

@@ -2918,7 +2918,6 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 {
 	struct usb_hub	*hub = usb_hub_to_struct_hub(udev->parent);
 	struct usb_port *port_dev = hub->ports[udev->portnum - 1];
-	enum pm_qos_flags_status pm_qos_stat;
 	int		port1 = udev->portnum;
 	int		status;
 	bool		really_suspend = true;
@@ -2956,7 +2955,7 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 					status);
 			/* bail if autosuspend is requested */
 			if (PMSG_IS_AUTO(msg))
-				return status;
+				goto err_wakeup;
 		}
 	}
 
@@ -2965,14 +2964,16 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 		usb_set_usb2_hardware_lpm(udev, 0);
 
 	if (usb_disable_ltm(udev)) {
-		dev_err(&udev->dev, "%s Failed to disable LTM before suspend\n.",
-				__func__);
-		return -ENOMEM;
+		dev_err(&udev->dev, "Failed to disable LTM before suspend\n.");
+		status = -ENOMEM;
+		if (PMSG_IS_AUTO(msg))
+			goto err_ltm;
 	}
 	if (usb_unlocked_disable_lpm(udev)) {
-		dev_err(&udev->dev, "%s Failed to disable LPM before suspend\n.",
-				__func__);
-		return -ENOMEM;
+		dev_err(&udev->dev, "Failed to disable LPM before suspend\n.");
+		status = -ENOMEM;
+		if (PMSG_IS_AUTO(msg))
+			goto err_lpm3;
 	}
 
 	/* see 7.1.7.6 */
@@ -3000,28 +3001,31 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 	if (status) {
 		dev_dbg(hub->intfdev, "can't suspend port %d, status %d\n",
 				port1, status);
-		/* paranoia:  "should not happen" */
-		if (udev->do_remote_wakeup) {
-			if (!hub_is_superspeed(hub->hdev)) {
-				(void) usb_control_msg(udev,
-						usb_sndctrlpipe(udev, 0),
-						USB_REQ_CLEAR_FEATURE,
-						USB_RECIP_DEVICE,
-						USB_DEVICE_REMOTE_WAKEUP, 0,
-						NULL, 0,
-						USB_CTRL_SET_TIMEOUT);
-			} else
-				(void) usb_disable_function_remotewakeup(udev);
-
-		}
 
+		/* Try to enable USB3 LPM and LTM again */
+		usb_unlocked_enable_lpm(udev);
+ err_lpm3:
+		usb_enable_ltm(udev);
+ err_ltm:
 		/* Try to enable USB2 hardware LPM again */
 		if (udev->usb2_hw_lpm_capable == 1)
 			usb_set_usb2_hardware_lpm(udev, 1);
 
-		/* Try to enable USB3 LTM and LPM again */
-		usb_enable_ltm(udev);
-		usb_unlocked_enable_lpm(udev);
+		if (udev->do_remote_wakeup) {
+			if (udev->speed < USB_SPEED_SUPER)
+				usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+						USB_REQ_CLEAR_FEATURE,
+						USB_RECIP_DEVICE,
+						USB_DEVICE_REMOTE_WAKEUP, 0,
+						NULL, 0, USB_CTRL_SET_TIMEOUT);
+			else
+				usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+						USB_REQ_CLEAR_FEATURE,
+						USB_RECIP_INTERFACE,
+						USB_INTRF_FUNC_SUSPEND, 0,
+						NULL, 0, USB_CTRL_SET_TIMEOUT);
+		}
+ err_wakeup:
 
 		/* System sleep transitions should never fail */
 		if (!PMSG_IS_AUTO(msg))
@@ -3043,14 +3047,15 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 	 * Check whether current status meets the requirement of
 	 * usb port power off mechanism
 	 */
-	pm_qos_stat = dev_pm_qos_flags(&port_dev->dev,
-			PM_QOS_FLAG_NO_POWER_OFF);
-	if (!udev->do_remote_wakeup
-			&& pm_qos_stat != PM_QOS_FLAGS_ALL
-			&& udev->persist_enabled
-			&& !status) {
-		pm_runtime_put_sync(&port_dev->dev);
-		port_dev->did_runtime_put = true;
+	if (status == 0 && !udev->do_remote_wakeup && udev->persist_enabled) {
+		enum pm_qos_flags_status pm_qos_stat;
+
+		pm_qos_stat = dev_pm_qos_flags(&port_dev->dev,
+				PM_QOS_FLAG_NO_POWER_OFF);
+		if (pm_qos_stat != PM_QOS_FLAGS_ALL) {
+			pm_runtime_put_sync(&port_dev->dev);
+			port_dev->did_runtime_put = true;
+		}
 	}
 
 	usb_mark_last_busy(hub->hdev);