USB: improve runtime remote wakeup settings

This patch (as1362) adjusts the way the USB autosuspend routines
handle remote-wakeup settings.  They aren't supposed to use
device_may_wakeup(); that test is intended only for system sleep, not
runtime power management.  Instead the code checks to see if any
interface drivers need remote wakeup; if they do then it is enabled,
provided the device is capable of it.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 8 insertions, 11 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index edff55a32575..271e857be0fa 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1486,9 +1486,6 @@ int usb_autoresume_device(struct usb_device *udev)
  * 0, a delayed autosuspend request for @intf's device is attempted.  The
  * attempt may fail (see autosuspend_check()).
  *
- * If the driver has set @intf->needs_remote_wakeup then autosuspend will
- * take place only if the device's remote-wakeup facility is enabled.
- *
  * This routine can run only in process context.
  */
 void usb_autopm_put_interface(struct usb_interface *intf)
@@ -1673,14 +1670,14 @@ EXPORT_SYMBOL_GPL(usb_autopm_get_interface_no_resume);
 /* Internal routine to check whether we may autosuspend a device. */
 static int autosuspend_check(struct usb_device *udev)
 {
-        int                     i;
+        int                     w, i;
         struct usb_interface    *intf;
         unsigned long           suspend_time, j;
 
         /* Fail if autosuspend is disabled, or any interfaces are in use, or
          * any interface drivers require remote wakeup but it isn't available.
          */
-        udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
+        w = 0;
         if (udev->actconfig) {
                 for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
                         intf = udev->actconfig->interface[i];
@@ -1694,12 +1691,7 @@ static int autosuspend_check(struct usb_device *udev)
                                 continue;
                         if (atomic_read(&intf->dev.power.usage_count) > 0)
                                 return -EBUSY;
-                        if (intf->needs_remote_wakeup &&
-                                        !udev->do_remote_wakeup) {
-                                dev_dbg(&udev->dev, "remote wakeup needed "
-                                                "for autosuspend\n");
-                                return -EOPNOTSUPP;
-                        }
+                        w |= intf->needs_remote_wakeup;
 
                         /* Don't allow autosuspend if the device will need
                          * a reset-resume and any of its interface drivers
@@ -1715,6 +1707,11 @@ static int autosuspend_check(struct usb_device *udev)
                         }
                 }
         }
+        if (w && !device_can_wakeup(&udev->dev)) {
+                dev_dbg(&udev->dev, "remote wakeup needed for autosuspend\n");
+                return -EOPNOTSUPP;
+        }
+        udev->do_remote_wakeup = w;
 
         /* If everything is okay but the device hasn't been idle for long
          * enough, queue a delayed autosuspend request.