usb: Using correct way to clear usb3.0 device's remote wakeup feature.

Usb3.0 device defines function remote wakeup which is only for interface
recipient rather than device recipient. This is different with usb2.0 device's
remote wakeup feature which is defined for device recipient. According usb3.0
spec 9.4.5, the function remote wakeup can be modified by the SetFeature()
requests using the FUNCTION_SUSPEND feature selector. This patch is to use
correct way to disable usb3.0 device's function remote wakeup after suspend
error and resuming.

This should be backported to kernels as old as 3.4, that contain the
commit 623bef9e "USB/xhci: Enable remote
wakeup for USB3 devices."
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org

drivers/usb/core/hub.c

@@ -2838,6 +2838,23 @@ void usb_enable_ltm(struct usb_device *udev)
 EXPORT_SYMBOL_GPL(usb_enable_ltm);
 
 #ifdef	CONFIG_USB_SUSPEND
+/*
+ * usb_disable_function_remotewakeup - disable usb3.0
+ * device's function remote wakeup
+ * @udev: target device
+ *
+ * Assume there's only one function on the USB 3.0
+ * device and disable remote wake for the first
+ * interface. FIXME if the interface association
+ * descriptor shows there's more than one function.
+ */
+static int usb_disable_function_remotewakeup(struct usb_device *udev)
+{
+	return 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);
+}
 
 /*
  * usb_port_suspend - suspend a usb device's upstream port
@@ -2955,12 +2972,19 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 		dev_dbg(hub->intfdev, "can't suspend port %d, status %d\n",
 				port1, status);
 		/* paranoia:  "should not happen" */
-		if (udev->do_remote_wakeup)
-			(void) usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
-				USB_REQ_CLEAR_FEATURE, USB_RECIP_DEVICE,
+		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 USB2 hardware LPM again */
 		if (udev->usb2_hw_lpm_capable == 1)
@@ -3052,8 +3076,9 @@ static int finish_port_resume(struct usb_device *udev)
 	 * udev->reset_resume
 	 */
 	} else if (udev->actconfig && !udev->reset_resume) {
+		if (!hub_is_superspeed(udev->parent)) {
 			le16_to_cpus(&devstatus);
-		if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP)) {
+			if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP))
 				status = usb_control_msg(udev,
 						usb_sndctrlpipe(udev, 0),
 						USB_REQ_CLEAR_FEATURE,
@@ -3061,11 +3086,20 @@ static int finish_port_resume(struct usb_device *udev)
 						USB_DEVICE_REMOTE_WAKEUP, 0,
 						NULL, 0,
 						USB_CTRL_SET_TIMEOUT);
+		} else {
+			status = usb_get_status(udev, USB_RECIP_INTERFACE, 0,
+					&devstatus);
+			le16_to_cpus(&devstatus);
+			if (!status && devstatus & (USB_INTRF_STAT_FUNC_RW_CAP
+					| USB_INTRF_STAT_FUNC_RW))
+				status =
+					usb_disable_function_remotewakeup(udev);
+		}
+
 		if (status)
 			dev_dbg(&udev->dev,
 				"disable remote wakeup, status %d\n",
 				status);
-		}
 		status = 0;
 	}
 	return status;

include/uapi/linux/usb/ch9.h

@@ -152,6 +152,12 @@
 #define USB_INTRF_FUNC_SUSPEND_LP	(1 << (8 + 0))
 #define USB_INTRF_FUNC_SUSPEND_RW	(1 << (8 + 1))
 
+/*
+ * Interface status, Figure 9-5 USB 3.0 spec
+ */
+#define USB_INTRF_STAT_FUNC_RW_CAP     1
+#define USB_INTRF_STAT_FUNC_RW         2
+
 #define USB_ENDPOINT_HALT		0	/* IN/OUT will STALL */
 
 /* Bit array elements as returned by the USB_REQ_GET_STATUS request. */