Power management fixes for 3.6-rc3

* Fixes for three obscure problems in the runtime PM core code found recently.
 * Two fixes for the new "coupled" cpuidle code from Colin Cross and
   Jon Medhurst.
 * intel_idle driver fix from Konrad Rzeszutek Wilk.
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Merge tag 'pm-for-3.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael J. Wysocki:
  - Fixes for three obscure problems in the runtime PM core code found
   recently.
 - Two fixes for the new "coupled" cpuidle code from Colin Cross and Jon
   Medhurst.
 - intel_idle driver fix from Konrad Rzeszutek Wilk.

* tag 'pm-for-3.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  intel_idle: Check cpu_idle_get_driver() for NULL before dereferencing it.
  cpuidle: Prevent null pointer dereference in cpuidle_coupled_cpu_notify
  cpuidle: coupled: fix sleeping while atomic in cpu notifier
  PM / Runtime: Check device PM QoS setting before "no callbacks" check
  PM / Runtime: Clear power.deferred_resume on success in rpm_suspend()
  PM / Runtime: Fix rpm_resume() return value for power.no_callbacks set

drivers/base/power/runtime.c

@@ -147,6 +147,8 @@ static int rpm_check_suspend_allowed(struct device *dev)
 	    || (dev->power.request_pending
 			&& dev->power.request == RPM_REQ_RESUME))
 		retval = -EAGAIN;
+	else if (__dev_pm_qos_read_value(dev) < 0)
+		retval = -EPERM;
 	else if (dev->power.runtime_status == RPM_SUSPENDED)
 		retval = 1;
 
@@ -388,7 +390,6 @@ static int rpm_suspend(struct device *dev, int rpmflags)
 		goto repeat;
 	}
 
-	dev->power.deferred_resume = false;
 	if (dev->power.no_callbacks)
 		goto no_callback;	/* Assume success. */
 
@@ -403,12 +404,6 @@ static int rpm_suspend(struct device *dev, int rpmflags)
 		goto out;
 	}
 
-	if (__dev_pm_qos_read_value(dev) < 0) {
-		/* Negative PM QoS constraint means "never suspend". */
-		retval = -EPERM;
-		goto out;
-	}
-
 	__update_runtime_status(dev, RPM_SUSPENDING);
 
 	if (dev->pm_domain)
@@ -440,6 +435,7 @@ static int rpm_suspend(struct device *dev, int rpmflags)
 	wake_up_all(&dev->power.wait_queue);
 
 	if (dev->power.deferred_resume) {
+		dev->power.deferred_resume = false;
 		rpm_resume(dev, 0);
 		retval = -EAGAIN;
 		goto out;
@@ -584,6 +580,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
 		    || dev->parent->power.runtime_status == RPM_ACTIVE) {
 			atomic_inc(&dev->parent->power.child_count);
 			spin_unlock(&dev->parent->power.lock);
+			retval = 1;
 			goto no_callback;	/* Assume success. */
 		}
 		spin_unlock(&dev->parent->power.lock);
@@ -664,7 +661,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
 	}
 	wake_up_all(&dev->power.wait_queue);
 
-	if (!retval)
+	if (retval >= 0)
 		rpm_idle(dev, RPM_ASYNC);
 
  out:

drivers/cpuidle/coupled.c

@@ -678,10 +678,22 @@ static int cpuidle_coupled_cpu_notify(struct notifier_block *nb,
 	int cpu = (unsigned long)hcpu;
 	struct cpuidle_device *dev;
 
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_UP_PREPARE:
+	case CPU_DOWN_PREPARE:
+	case CPU_ONLINE:
+	case CPU_DEAD:
+	case CPU_UP_CANCELED:
+	case CPU_DOWN_FAILED:
+		break;
+	default:
+		return NOTIFY_OK;
+	}
+
 	mutex_lock(&cpuidle_lock);
 
 	dev = per_cpu(cpuidle_devices, cpu);
-	if (!dev->coupled)
+	if (!dev || !dev->coupled)
 		goto out;
 
 	switch (action & ~CPU_TASKS_FROZEN) {

drivers/idle/intel_idle.c

@@ -606,8 +606,9 @@ static int __init intel_idle_init(void)
 	intel_idle_cpuidle_driver_init();
 	retval = cpuidle_register_driver(&intel_idle_driver);
 	if (retval) {
+		struct cpuidle_driver *drv = cpuidle_get_driver();
 		printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
-			cpuidle_get_driver()->name);
+			drv ? drv->name : "none");
 		return retval;
 	}