4 files changed, 49 insertions, 9 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index f7841d44feda..689433cdef25 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1790,6 +1790,9 @@ int usb_set_usb2_hardware_lpm(struct usb_device *udev, int enable)
 	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
 	int ret = -EPERM;
 
+	if (enable && !udev->usb2_hw_lpm_allowed)
+		return 0;
+
 	if (hcd->driver->set_usb2_hw_lpm) {
 		ret = hcd->driver->set_usb2_hw_lpm(hcd, udev, enable);
 		if (!ret)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 92dde941fdbe..06cec635e703 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1112,16 +1112,13 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
 			/*
 			 * USB3 protocol ports will automatically transition
 			 * to Enabled state when detect an USB3.0 device attach.
-			 * Do not disable USB3 protocol ports.
+			 * Do not disable USB3 protocol ports, just pretend
+			 * power was lost
 			 */
-			if (!hub_is_superspeed(hdev)) {
+			portstatus &= ~USB_PORT_STAT_ENABLE;
+			if (!hub_is_superspeed(hdev))
 				usb_clear_port_feature(hdev, port1,
 						   USB_PORT_FEAT_ENABLE);
-				portstatus &= ~USB_PORT_STAT_ENABLE;
-			} else {
-				/* Pretend that power was lost for USB3 devs */
-				portstatus &= ~USB_PORT_STAT_ENABLE;
-			}
 		}
 
 		/* Clear status-change flags; we'll debounce later */
@@ -3958,6 +3955,32 @@ static int hub_set_address(struct usb_device *udev, int devnum)
 	return retval;
 }
 
+/*
+ * There are reports of USB 3.0 devices that say they support USB 2.0 Link PM
+ * when they're plugged into a USB 2.0 port, but they don't work when LPM is
+ * enabled.
+ *
+ * Only enable USB 2.0 Link PM if the port is internal (hardwired), or the
+ * device says it supports the new USB 2.0 Link PM errata by setting the BESL
+ * support bit in the BOS descriptor.
+ */
+static void hub_set_initial_usb2_lpm_policy(struct usb_device *udev)
+{
+	int connect_type;
+
+	if (!udev->usb2_hw_lpm_capable)
+		return;
+
+	connect_type = usb_get_hub_port_connect_type(udev->parent,
+			udev->portnum);
+
+	if ((udev->bos->ext_cap->bmAttributes & USB_BESL_SUPPORT) ||
+			connect_type == USB_PORT_CONNECT_TYPE_HARD_WIRED) {
+		udev->usb2_hw_lpm_allowed = 1;
+		usb_set_usb2_hardware_lpm(udev, 1);
+	}
+}
+
 /* Reset device, (re)assign address, get device descriptor.
  * Device connection must be stable, no more debouncing needed.
  * Returns device in USB_STATE_ADDRESS, except on error.
@@ -4251,6 +4274,7 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
 	/* notify HCD that we have a device connected and addressed */
 	if (hcd->driver->update_device)
 		hcd->driver->update_device(hcd, udev);
+	hub_set_initial_usb2_lpm_policy(udev);
 fail:
 	if (retval) {
 		hub_port_disable(hub, port1, 0);
@@ -5095,6 +5119,12 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
 	}
 	parent_hub = usb_hub_to_struct_hub(parent_hdev);
 
+	/* Disable USB2 hardware LPM.
+	 * It will be re-enabled by the enumeration process.
+	 */
+	if (udev->usb2_hw_lpm_enabled == 1)
+		usb_set_usb2_hardware_lpm(udev, 0);
+
 	bos = udev->bos;
 	udev->bos = NULL;
 
@@ -5202,6 +5232,7 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
 
 done:
 	/* Now that the alt settings are re-installed, enable LTM and LPM. */
+	usb_set_usb2_hardware_lpm(udev, 1);
 	usb_unlocked_enable_lpm(udev);
 	usb_enable_ltm(udev);
 	usb_release_bos_descriptor(udev);
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 82927e1ed27d..bb315970e475 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1182,8 +1182,12 @@ void usb_disable_device(struct usb_device *dev, int skip_ep0)
 			put_device(&dev->actconfig->interface[i]->dev);
 			dev->actconfig->interface[i] = NULL;
 		}
+
+		if (dev->usb2_hw_lpm_enabled == 1)
+			usb_set_usb2_hardware_lpm(dev, 0);
 		usb_unlocked_disable_lpm(dev);
 		usb_disable_ltm(dev);
+
 		dev->actconfig = NULL;
 		if (dev->state == USB_STATE_CONFIGURED)
 			usb_set_device_state(dev, USB_STATE_ADDRESS);
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 5cf431b0424c..52a97adf02a0 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -458,7 +458,7 @@ static ssize_t usb2_hardware_lpm_show(struct device *dev,
 	struct usb_device *udev = to_usb_device(dev);
 	const char *p;
 
-	if (udev->usb2_hw_lpm_enabled == 1)
+	if (udev->usb2_hw_lpm_allowed == 1)
 		p = "enabled";
 	else
 		p = "disabled";
@@ -478,8 +478,10 @@ static ssize_t usb2_hardware_lpm_store(struct device *dev,
 
 	ret = strtobool(buf, &value);
 
-	if (!ret)
+	if (!ret) {
+		udev->usb2_hw_lpm_allowed = value;
 		ret = usb_set_usb2_hardware_lpm(udev, value);
+	}
 
 	usb_unlock_device(udev);