Add a notifier for _CST changing events. It is necessary to unload
the processor idle handle for a short period of time to avoid for nasty
races -- and we don't want to grab too many locks so that the idle handler
continues to be speedy.

Signed-off-by: Dominik Brodowski <linux@brodo.de>

 drivers/acpi/processor_core.c |    2 +-
 drivers/acpi/processor_idle.c |   27 +++++++++++++++++++++++++++
 include/acpi/processor.h      |    1 +
 3 files changed, 29 insertions(+), 1 deletion(-)

diff -ruN linux-original/drivers/acpi/processor_core.c linux/drivers/acpi/processor_core.c
--- linux-original/drivers/acpi/processor_core.c	2004-11-27 19:37:15.000000000 +0100
+++ linux/drivers/acpi/processor_core.c	2004-11-27 21:37:07.644320800 +0100
@@ -627,7 +627,7 @@
 			pr->performance_platform_limit);
 		break;
 	case ACPI_PROCESSOR_NOTIFY_POWER:
-		/* TBD */
+		acpi_processor_cst_has_changed(pr);
 		acpi_bus_generate_event(device, event, 0);
 		break;
 	default:
diff -ruN linux-original/drivers/acpi/processor_idle.c linux/drivers/acpi/processor_idle.c
--- linux-original/drivers/acpi/processor_idle.c	2004-11-27 21:25:00.000000000 +0100
+++ linux/drivers/acpi/processor_idle.c	2004-11-27 21:36:15.538242128 +0100
@@ -778,6 +778,32 @@
 	return_VALUE(0);
 }
 
+int acpi_processor_cst_has_changed (struct acpi_processor *pr)
+{
+ 	int			result = 0;
+
+	ACPI_FUNCTION_TRACE("acpi_processor_cst_has_changed");
+
+	if (!pr)
+ 		return_VALUE(-EINVAL);
+
+	if (errata.smp) {
+		return_VALUE(-ENODEV);
+	}
+
+	/* Fall back to the default idle loop */
+	pm_idle = pm_idle_save;
+	pm_idle_save = NULL;
+
+	pr->flags.power = 0;
+	result = acpi_processor_get_power_info(pr);
+	if (pr->flags.power == 1) {
+		pm_idle_save = pm_idle;
+		pm_idle = acpi_processor_idle;
+	}
+
+	return_VALUE(result);
+}
 
 /* proc interface */
 
@@ -857,3 +883,4 @@
 	.llseek		= seq_lseek,
 	.release	= single_release,
 };
+
diff -ruN linux-original/include/acpi/processor.h linux/include/acpi/processor.h
--- linux-original/include/acpi/processor.h	2004-11-27 21:25:00.000000000 +0100
+++ linux/include/acpi/processor.h	2004-11-27 21:36:27.479426792 +0100
@@ -214,6 +214,7 @@
 int acpi_processor_get_power_info (struct acpi_processor *pr);
 extern struct file_operations acpi_processor_power_fops;
 int no_c2c3(struct dmi_system_id *id);
+int acpi_processor_cst_has_changed (struct acpi_processor *pr);
 
 /* in processor_thermal.c */
 int acpi_processor_get_limit_info (struct acpi_processor *pr);