1 files changed, 53 insertions, 1 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index f6f81c85c5c..f536aebc958 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -288,6 +288,7 @@ static int usb_probe_interface(struct device *dev)
 	struct usb_device *udev = interface_to_usbdev(intf);
 	const struct usb_device_id *id;
 	int error = -ENODEV;
+	int lpm_disable_error;
 
 	dev_dbg(dev, "%s\n", __func__);
 
@@ -324,6 +325,25 @@ static int usb_probe_interface(struct device *dev)
 	if (driver->supports_autosuspend)
 		pm_runtime_enable(dev);
 
+	/* If the new driver doesn't allow hub-initiated LPM, and we can't
+	 * disable hub-initiated LPM, then fail the probe.
+	 *
+	 * Otherwise, leaving LPM enabled should be harmless, because the
+	 * endpoint intervals should remain the same, and the U1/U2 timeouts
+	 * should remain the same.
+	 *
+	 * If we need to install alt setting 0 before probe, or another alt
+	 * setting during probe, that should also be fine.  usb_set_interface()
+	 * will attempt to disable LPM, and fail if it can't disable it.
+	 */
+	lpm_disable_error = usb_unlocked_disable_lpm(udev);
+	if (lpm_disable_error && driver->disable_hub_initiated_lpm) {
+		dev_err(&intf->dev, "%s Failed to disable LPM for driver %s\n.",
+				__func__, driver->name);
+		error = lpm_disable_error;
+		goto err;
+	}
+
 	/* Carry out a deferred switch to altsetting 0 */
 	if (intf->needs_altsetting0) {
 		error = usb_set_interface(udev, intf->altsetting[0].
@@ -338,6 +358,11 @@ static int usb_probe_interface(struct device *dev)
 		goto err;
 
 	intf->condition = USB_INTERFACE_BOUND;
+
+	/* If the LPM disable succeeded, balance the ref counts. */
+	if (!lpm_disable_error)
+		usb_unlocked_enable_lpm(udev);
+
 	usb_autosuspend_device(udev);
 	return error;
 
@@ -361,7 +386,7 @@ static int usb_unbind_interface(struct device *dev)
 	struct usb_driver *driver = to_usb_driver(dev->driver);
 	struct usb_interface *intf = to_usb_interface(dev);
 	struct usb_device *udev;
-	int error, r;
+	int error, r, lpm_disable_error;
 
 	intf->condition = USB_INTERFACE_UNBINDING;
 
@@ -369,6 +394,13 @@ static int usb_unbind_interface(struct device *dev)
 	udev = interface_to_usbdev(intf);
 	error = usb_autoresume_device(udev);
 
+	/* Hub-initiated LPM policy may change, so attempt to disable LPM until
+	 * the driver is unbound.  If LPM isn't disabled, that's fine because it
+	 * wouldn't be enabled unless all the bound interfaces supported
+	 * hub-initiated LPM.
+	 */
+	lpm_disable_error = usb_unlocked_disable_lpm(udev);
+
 	/* Terminate all URBs for this interface unless the driver
 	 * supports "soft" unbinding.
 	 */
@@ -402,6 +434,10 @@ static int usb_unbind_interface(struct device *dev)
 	intf->condition = USB_INTERFACE_UNBOUND;
 	intf->needs_remote_wakeup = 0;
 
+	/* Attempt to re-enable USB3 LPM, if the disable succeeded. */
+	if (!lpm_disable_error)
+		usb_unlocked_enable_lpm(udev);
+
 	/* Unbound interfaces are always runtime-PM-disabled and -suspended */
 	if (driver->supports_autosuspend)
 		pm_runtime_disable(dev);
@@ -442,17 +478,29 @@ int usb_driver_claim_interface(struct usb_driver *driver,
 				struct usb_interface *iface, void *priv)
 {
 	struct device *dev = &iface->dev;
+	struct usb_device *udev;
 	int retval = 0;
+	int lpm_disable_error;
 
 	if (dev->driver)
 		return -EBUSY;
 
+	udev = interface_to_usbdev(iface);
+
 	dev->driver = &driver->drvwrap.driver;
 	usb_set_intfdata(iface, priv);
 	iface->needs_binding = 0;
 
 	iface->condition = USB_INTERFACE_BOUND;
 
+	/* Disable LPM until this driver is bound. */
+	lpm_disable_error = usb_unlocked_disable_lpm(udev);
+	if (lpm_disable_error && driver->disable_hub_initiated_lpm) {
+		dev_err(&iface->dev, "%s Failed to disable LPM for driver %s\n.",
+				__func__, driver->name);
+		return -ENOMEM;
+	}
+
 	/* Claimed interfaces are initially inactive (suspended) and
 	 * runtime-PM-enabled, but only if the driver has autosuspend
 	 * support.  Otherwise they are marked active, to prevent the
@@ -471,6 +519,10 @@ int usb_driver_claim_interface(struct usb_driver *driver,
 	if (device_is_registered(dev))
 		retval = device_bind_driver(dev);
 
+	/* Attempt to re-enable USB3 LPM, if the disable was successful. */
+	if (!lpm_disable_error)
+		usb_unlocked_enable_lpm(udev);
+
 	return retval;
 }
 EXPORT_SYMBOL_GPL(usb_driver_claim_interface);