1 files changed, 46 insertions, 69 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 22b051b94a86..4166090db642 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -51,7 +51,7 @@ module_param(latency_factor, uint, 0644);
 
 static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
 
-static struct cpuidle_driver acpi_idle_driver = {
+struct cpuidle_driver acpi_idle_driver = {
 	.name =		"acpi_idle",
 	.owner =	THIS_MODULE,
 };
@@ -1357,102 +1357,79 @@ int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
 	return 0;
 }
 
-void acpi_processor_register_idle_driver(void)
-{
-	struct acpi_processor *pr;
-	int ret = -ENODEV;
-	int cpu;
-
-	/*
-	 * Acpi idle driver is used by all possible CPUs.
-	 * Install the idle handler by the processor power info of one in them.
-	 * Note that we use previously set idle handler will be used on
-	 * platforms that only support C1.
-	 */
-	for_each_cpu(cpu, (struct cpumask *)cpu_possible_mask) {
-		pr = per_cpu(processors, cpu);
-		if (!pr)
-			continue;
-
-		ret = acpi_processor_get_power_info(pr);
-		if (!ret) {
-			pr->flags.power_setup_done = 1;
-			acpi_processor_setup_cpuidle_states(pr);
-			break;
-		}
-	}
-
-	if (ret) {
-		pr_debug("No ACPI power information from any CPUs.\n");
-		return;
-	}
+static int acpi_processor_registered;
 
-	ret = cpuidle_register_driver(&acpi_idle_driver);
-	if (ret) {
-		pr_debug("register %s failed.\n", acpi_idle_driver.name);
-		return;
-	}
-	pr_debug("%s registered with cpuidle.\n", acpi_idle_driver.name);
-}
-
-void acpi_processor_unregister_idle_driver(void)
-{
-	cpuidle_unregister_driver(&acpi_idle_driver);
-}
-
-void acpi_processor_power_init(struct acpi_processor *pr)
+int acpi_processor_power_init(struct acpi_processor *pr)
 {
+	int retval;
 	struct cpuidle_device *dev;
 
-	/*
-	 * The code below only works if the current cpuidle driver is the ACPI
-	 * idle driver.
-	 */
-	if (cpuidle_get_driver() != &acpi_idle_driver)
-		return;
-
 	if (disabled_by_idle_boot_param())
-		return;
+		return 0;
 
 	acpi_processor_cstate_first_run_checks();
 
 	if (!acpi_processor_get_power_info(pr))
 		pr->flags.power_setup_done = 1;
 
-	if (!pr->flags.power)
-		return;
-
-	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
-	if (!dev)
-		return;
+	/*
+	 * Install the idle handler if processor power management is supported.
+	 * Note that we use previously set idle handler will be used on
+	 * platforms that only support C1.
+	 */
+	if (pr->flags.power) {
+		/* Register acpi_idle_driver if not already registered */
+		if (!acpi_processor_registered) {
+			acpi_processor_setup_cpuidle_states(pr);
+			retval = cpuidle_register_driver(&acpi_idle_driver);
+			if (retval)
+				return retval;
+			pr_debug("%s registered with cpuidle\n",
+				 acpi_idle_driver.name);
+		}
 
-	per_cpu(acpi_cpuidle_device, pr->id) = dev;
+		dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+		if (!dev)
+			return -ENOMEM;
+		per_cpu(acpi_cpuidle_device, pr->id) = dev;
 
-	acpi_processor_setup_cpuidle_dev(pr, dev);
+		acpi_processor_setup_cpuidle_dev(pr, dev);
 
-	/*
-	 * Register a cpuidle device for this CPU.  The cpuidle driver using
-	 * this device is expected to be registered.
-	 */
-	if (cpuidle_register_device(dev)) {
-		per_cpu(acpi_cpuidle_device, pr->id) = NULL;
-		kfree(dev);
+		/* Register per-cpu cpuidle_device. Cpuidle driver
+		 * must already be registered before registering device
+		 */
+		retval = cpuidle_register_device(dev);
+		if (retval) {
+			if (acpi_processor_registered == 0)
+				cpuidle_unregister_driver(&acpi_idle_driver);
+
+			per_cpu(acpi_cpuidle_device, pr->id) = NULL;
+			kfree(dev);
+			return retval;
+		}
+		acpi_processor_registered++;
 	}
+	return 0;
 }
 
-void acpi_processor_power_exit(struct acpi_processor *pr)
+int acpi_processor_power_exit(struct acpi_processor *pr)
 {
 	struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
 
 	if (disabled_by_idle_boot_param())
-		return;
+		return 0;
 
 	if (pr->flags.power) {
 		cpuidle_unregister_device(dev);
+		acpi_processor_registered--;
+		if (acpi_processor_registered == 0)
+			cpuidle_unregister_driver(&acpi_idle_driver);
+
 		kfree(dev);
 	}
 
 	pr->flags.power_setup_done = 0;
+	return 0;
 }
 
 MODULE_IMPORT_NS("ACPI_PROCESSOR_IDLE");