usb: fix hub-port pm_runtime_enable() vs runtime pm transitions

[deliverable/linux.git] / drivers / usb / core / port.c

diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 9347ade7d5fe3637fcb2aa8514831e1b5da2247c..fe1b6d0967e32a95e270fcccee8e8b72eb844db3 100644 (file)
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -68,6 +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);
 }
 
@@ -400,9 +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;
@@ -418,31 +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)