From: Lv Zheng <lv.zheng@intel.com>
Date: Fri, 16 Nov 2012 01:46:28 +0000 (+0100)
Subject: ACPI / PM: Add check preventing transitioning to non-D0 state from D3.
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ddc150f7a33ae0c9cb16eaac3641abc00f56316f;p=linux-beck.git

ACPI / PM: Add check preventing transitioning to non-D0 state from D3.

No power transitioning from D3 state up to a non-D0 state is allowed
so make acpi_device_set_power() fail and complain if such a transition
is attempted.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 07a20ee3e690..1f0d457ecbcf 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -306,6 +306,12 @@ int acpi_device_set_power(struct acpi_device *device, int state)
 	 * a lower-powered state.
 	 */
 	if (state < device->power.state) {
+		if (device->power.state >= ACPI_STATE_D3_HOT &&
+		    state != ACPI_STATE_D0) {
+			printk(KERN_WARNING PREFIX
+			      "Cannot transition to non-D0 state from D3\n");
+			return -ENODEV;
+		}
 		if (device->power.flags.power_resources) {
 			result = acpi_power_transition(device, state);
 			if (result)