1 files changed, 65 insertions, 24 deletions

diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 62036faf56c0..fe1b6d0967e3 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -21,6 +21,8 @@
 
 #include "hub.h"
 
+static int usb_port_block_power_off;
+
 static const struct attribute_group *port_dev_group[];
 
 static ssize_t connect_type_show(struct device *dev,
@@ -66,6 +68,7 @@ static void usb_port_device_release(struct device *dev)
 {
         struct usb_port *port_dev = to_usb_port(dev);
 
+        kfree(port_dev->req);
         kfree(port_dev);
 }
 
@@ -142,6 +145,9 @@ static int usb_port_runtime_suspend(struct device *dev)
                         == PM_QOS_FLAGS_ALL)
                 return -EAGAIN;
 
+        if (usb_port_block_power_off)
+                return -EBUSY;
+
         usb_autopm_get_interface(intf);
         retval = usb_hub_set_port_power(hdev, hub, port1, false);
         usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
@@ -190,11 +196,19 @@ static int link_peers(struct usb_port *left, struct usb_port *right)
         if (left->peer || right->peer) {
                 struct usb_port *lpeer = left->peer;
                 struct usb_port *rpeer = right->peer;
-
-                WARN(1, "failed to peer %s and %s (%s -> %p) (%s -> %p)\n",
-                        dev_name(&left->dev), dev_name(&right->dev),
-                        dev_name(&left->dev), lpeer,
-                        dev_name(&right->dev), rpeer);
+                char *method;
+
+                if (left->location && left->location == right->location)
+                        method = "location";
+                else
+                        method = "default";
+
+                pr_warn("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
+                        dev_name(&left->dev), dev_name(&right->dev), method,
+                        dev_name(&left->dev),
+                        lpeer ? dev_name(&lpeer->dev) : "none",
+                        dev_name(&right->dev),
+                        rpeer ? dev_name(&rpeer->dev) : "none");
                 return -EBUSY;
         }
 
@@ -251,6 +265,7 @@ static void link_peers_report(struct usb_port *left, struct usb_port *right)
                 dev_warn(&left->dev, "failed to peer to %s (%d)\n",
                                 dev_name(&right->dev), rc);
                 pr_warn_once("usb: port power management may be unreliable\n");
+                usb_port_block_power_off = 1;
         }
 }
 
@@ -386,9 +401,13 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
         int retval;
 
         port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
-        if (!port_dev) {
-                retval = -ENOMEM;
-                goto exit;
+        if (!port_dev)
+                return -ENOMEM;
+
+        port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);
+        if (!port_dev->req) {
+                kfree(port_dev);
+                return -ENOMEM;
         }
 
         hub->ports[port1 - 1] = port_dev;
@@ -404,31 +423,53 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
                         port1);
         mutex_init(&port_dev->status_lock);
         retval = device_register(&port_dev->dev);
-        if (retval)
-                goto error_register;
+        if (retval) {
+                put_device(&port_dev->dev);
+                return retval;
+        }
+
+        /* Set default policy of port-poweroff disabled. */
+        retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,
+                        DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);
+        if (retval < 0) {
+                device_unregister(&port_dev->dev);
+                return retval;
+        }
 
         find_and_link_peer(hub, port1);
 
+        /*
+         * Enable runtime pm and hold a refernce that hub_configure()
+         * will drop once the PM_QOS_NO_POWER_OFF flag state has been set
+         * and the hub has been fully registered (hdev->maxchild set).
+         */
         pm_runtime_set_active(&port_dev->dev);
+        pm_runtime_get_noresume(&port_dev->dev);
+        pm_runtime_enable(&port_dev->dev);
+        device_enable_async_suspend(&port_dev->dev);
 
         /*
-         * Do not enable port runtime pm if the hub does not support
-         * power switching.  Also, userspace must have final say of
-         * whether a port is permitted to power-off.  Do not enable
-         * runtime pm if we fail to expose pm_qos_no_power_off.
+         * Keep hidden the ability to enable port-poweroff if the hub
+         * does not support power switching.
          */
-        if (hub_is_port_power_switchable(hub)
-                        && dev_pm_qos_expose_flags(&port_dev->dev,
-                        PM_QOS_FLAG_NO_POWER_OFF) == 0)
-                pm_runtime_enable(&port_dev->dev);
+        if (!hub_is_port_power_switchable(hub))
+                return 0;
 
-        device_enable_async_suspend(&port_dev->dev);
-        return 0;
+        /* Attempt to let userspace take over the policy. */
+        retval = dev_pm_qos_expose_flags(&port_dev->dev,
+                        PM_QOS_FLAG_NO_POWER_OFF);
+        if (retval < 0) {
+                dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");
+                return 0;
+        }
 
-error_register:
-        put_device(&port_dev->dev);
-exit:
-        return retval;
+        /* Userspace owns the policy, drop the kernel 'no_poweroff' request. */
+        retval = dev_pm_qos_remove_request(port_dev->req);
+        if (retval >= 0) {
+                kfree(port_dev->req);
+                port_dev->req = NULL;
+        }
+        return 0;
 }
 
 void usb_hub_remove_port_device(struct usb_hub *hub, int port1)