+int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+{
+ int cpu;
+ struct acpi_processor *_pr;
+
+ if (disabled_by_idle_boot_param())
+ return 0;
+
+ if (!pr)
+ return -EINVAL;
+
+ if (nocst)
+ return -ENODEV;
+
+ if (!pr->flags.power_setup_done)
+ return -ENODEV;
+
+ /*
+ * FIXME: Design the ACPI notification to make it once per
+ * system instead of once per-cpu. This condition is a hack
+ * to make the code that updates C-States be called once.
+ */
+
+ if (smp_processor_id() == 0 &&
+ cpuidle_get_driver() == &acpi_idle_driver) {
+
+ cpuidle_pause_and_lock();
+ /* Protect against cpu-hotplug */
+ get_online_cpus();
+
+ /* Disable all cpuidle devices */
+ for_each_online_cpu(cpu) {
+ _pr = per_cpu(processors, cpu);
+ if (!_pr || !_pr->flags.power_setup_done)
+ continue;
+ cpuidle_disable_device(&_pr->power.dev);
+ }
+
+ /* Populate Updated C-state information */
+ acpi_processor_setup_cpuidle_states(pr);
+
+ /* Enable all cpuidle devices */
+ for_each_online_cpu(cpu) {
+ _pr = per_cpu(processors, cpu);
+ if (!_pr || !_pr->flags.power_setup_done)
+ continue;
+ acpi_processor_get_power_info(_pr);
+ if (_pr->flags.power) {
+ acpi_processor_setup_cpuidle_cx(_pr);
+ cpuidle_enable_device(&_pr->power.dev);
+ }
+ }
+ put_online_cpus();
+ cpuidle_resume_and_unlock();
+ }
+
+ return 0;
+}
+
+static int acpi_processor_registered;
+