Move all port power policy evaluation to usb_port_runtime_suspend().
Makes it clearer what blocks port power off and is preparation for
follow on changes that
1/ make a usb_port a proper (device model) parent
   of a usb_device
2/ advertise to userspace what constraints are keeping a
   port powered
3/ changing the meaning of the usb_port runtime suspended
   state.
4/ add new constraints peer-port-power-state and connect_type

Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
 drivers/usb/core/hub.c  |   16 +++++++++++++++-
 drivers/usb/core/hub.h  |    7 +++++++
 drivers/usb/core/port.c |   22 ++++++++++++++++++++--
 3 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 683f528f5ea7..0e4c85380760 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2066,6 +2066,20 @@ void usb_disconnect(struct usb_device **pdev)
        put_device(&udev->dev);
 }
 
+/* outside of khubd context a device may be deleted at any time */
+struct usb_device *usb_port_get_child(struct usb_port *port_dev)
+{
+       struct usb_device *udev = NULL;
+
+       spin_lock_irq(&device_state_lock);
+       udev = port_dev->child;
+       if (udev)
+               get_device(&udev->dev);
+       spin_unlock_irq(&device_state_lock);
+
+       return udev;
+}
+
 #ifdef CONFIG_USB_ANNOUNCE_NEW_DEVICES
 static void show_string(struct usb_device *udev, char *id, char *string)
 {
@@ -3039,7 +3053,7 @@ int usb_port_suspend(struct usb_device *udev, 
pm_message_t msg)
                usb_set_device_state(udev, USB_STATE_SUSPENDED);
        }
 
-       if (status == 0 && !udev->do_remote_wakeup && udev->persist_enabled) {
+       if (status == 0) {
                pm_runtime_put_sync(&port_dev->dev);
                port_dev->did_runtime_put = true;
        }
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 44508d41c095..4e34365e41e3 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -110,3 +110,10 @@ extern int usb_set_port_feature(struct usb_device *hdev,
 extern void usb_assign_port_poweroff(struct usb_hub *hub, int port1, int val);
 #define usb_set_port_poweroff(h, p) usb_assign_port_poweroff(h, p, 1)
 #define usb_clear_port_poweroff(h, p) usb_assign_port_poweroff(h, p, 0)
+extern struct usb_device *usb_port_get_child(struct usb_port *port_dev);
+static inline void usb_port_put_child(struct usb_device *udev)
+{
+       if (!udev)
+               return;
+       put_device(&udev->dev);
+}
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 094a9d0e31c7..6257c1ec5e2d 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -93,6 +93,25 @@ static int usb_port_runtime_resume(struct device *dev)
        return retval;
 }
 
+static const char *power_on_reason(struct usb_port *port_dev)
+{
+       s32 flag = PM_QOS_FLAG_NO_POWER_OFF;
+       const char *reason = NULL;
+       struct usb_device *udev;
+
+       if (dev_pm_qos_flags(&port_dev->dev, flag) == PM_QOS_FLAGS_ALL)
+               return "pm_qos_no_power_off";
+
+       udev = usb_port_get_child(port_dev);
+       if (udev && udev->do_remote_wakeup)
+               reason = "wakeup enabled";
+       else if (udev && !udev->persist_enabled)
+               reason = "persist disabled";
+       usb_port_put_child(udev);
+
+       return reason;
+}
+
 static int usb_port_runtime_suspend(struct device *dev)
 {
        struct usb_port *port_dev = to_usb_port(dev);
@@ -105,8 +124,7 @@ static int usb_port_runtime_suspend(struct device *dev)
        if (!hub)
                return -EINVAL;
 
-       if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
-                       == PM_QOS_FLAGS_ALL)
+       if (power_on_reason(port_dev))
                return -EAGAIN;
 
        usb_autopm_get_interface(intf);

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