ACPI: Fix D3hot v D3cold confusion

Before this patch, ACPI_STATE_D3 incorrectly referenced D3hot
in some places, but D3cold in other places.

After this patch, ACPI_STATE_D3 always means ACPI_STATE_D3_COLD;
and all references to D3hot use ACPI_STATE_D3_HOT.

ACPI's _PR3 method is used to enter both D3hot and D3cold states.
What distinguishes D3hot from D3cold is the presence _PR3
(Power Resources for D3hot)  If these resources are all ON,
then the state is D3hot.  If _PR3 is not present,
or all _PR0 resources for the devices are OFF,
then the state is D3cold.

This patch applies after Linux-3.4-rc1.
A future syntax cleanup may remove ACPI_STATE_D3
to emphasize that it always means ACPI_STATE_D3_COLD.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Aaron Lu <aaron.lu@amd.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 7 insertions, 10 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 767e2dc..7417267 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -869,7 +869,7 @@ static int acpi_bus_get_power_flags(struct acpi_device *device)
 	/*
 	 * Enumerate supported power management states
 	 */
-	for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3; i++) {
+	for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
 		struct acpi_device_power_state *ps = &device->power.states[i];
 		char object_name[5] = { '_', 'P', 'R', '0' + i, '\0' };
 
@@ -884,21 +884,18 @@ static int acpi_bus_get_power_flags(struct acpi_device *device)
 				acpi_bus_add_power_resource(ps->resources.handles[j]);
 		}
 
-		/* The exist of _PR3 indicates D3Cold support */
-		if (i == ACPI_STATE_D3) {
-			status = acpi_get_handle(device->handle, object_name, &handle);
-			if (ACPI_SUCCESS(status))
-				device->power.states[ACPI_STATE_D3_COLD].flags.valid = 1;
-		}
-
 		/* Evaluate "_PSx" to see if we can do explicit sets */
 		object_name[2] = 'S';
 		status = acpi_get_handle(device->handle, object_name, &handle);
 		if (ACPI_SUCCESS(status))
 			ps->flags.explicit_set = 1;
 
-		/* State is valid if we have some power control */
-		if (ps->resources.count || ps->flags.explicit_set)
+		/*
+		 * State is valid if there are means to put the device into it.
+		 * D3hot is only valid if _PR3 present.
+		 */
+		if (ps->resources.count ||
+		    (ps->flags.explicit_set && i < ACPI_STATE_D3_HOT))
 			ps->flags.valid = 1;
 
 		ps->power = -1;	/* Unknown - driver assigned */