PM: Remove prev_state from struct dev_pm_info

The prev_state member of struct dev_pm_info (defined in include/linux/pm.h) is
only used during a resume to check if the device's state before the suspend was
'off', in which case the device is not resumed.  However, in such cases the
decision whether or not to resume the device should be made on the driver level
and the resume callbacks from the device's bus and class should be executed
anyway (the may be needed for some things other than just powering on the
device).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/base/power/resume.c

@@ -88,8 +88,7 @@ void dpm_resume(void)
 		list_move_tail(entry, &dpm_active);
 
 		mutex_unlock(&dpm_list_mtx);
-		if (!dev->power.prev_state.event)
+		resume_device(dev);
-			resume_device(dev);
 		mutex_lock(&dpm_list_mtx);
 		put_device(dev);
 	}

drivers/base/power/suspend.c

@@ -71,8 +71,6 @@ int suspend_device(struct device * dev, pm_message_t state)
 			dev->parent->power.power_state.event);
 	}
 
-	dev->power.prev_state = dev->power.power_state;
-
 	if (dev->class && dev->class->suspend && !dev->power.power_state.event) {
 		suspend_device_dbg(dev, state, "class ");
 		error = dev->class->suspend(dev, state);

drivers/usb/core/hub.c

@@ -1109,11 +1109,6 @@ void usb_root_hub_lost_power(struct usb_device *rhdev)
 
 	dev_warn(&rhdev->dev, "root hub lost power or was reset\n");
 
-	/* Make sure no potential wakeup events get lost,
-	 * by forcing the root hub to be resumed.
-	 */
-	rhdev->dev.power.prev_state.event = PM_EVENT_ON;
-
 	spin_lock_irqsave(&device_state_lock, flags);
 	hub = hdev_to_hub(rhdev);
 	for (port1 = 1; port1 <= rhdev->maxchild; ++port1) {

include/linux/pm.h

@@ -267,7 +267,6 @@ struct dev_pm_info {
 	unsigned		can_wakeup:1;
 #ifdef	CONFIG_PM
 	unsigned		should_wakeup:1;
-	pm_message_t		prev_state;
 	struct list_head	entry;
 #endif
 };