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Hibernation: Prepare to enter the low power state

PATCH New Rafael J. Wysocki 1 participant 1 message May 25, 2007

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Rafael J. Wysocki

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PATCH 1/1 Hibernation: Prepare to enter the low power state

From: Rafael J. Wysocki <[email protected]>

During hibernation we call hibernation_ops->prepare() before creating the image, but then, before saving it, we cancel the power transition by calling hibernation_ops->finish(). Thus prior to calling hibernation_ops->enter() we should let the platform firmware know that we're going to enter the low power state after all.

Signed-off-by Rafael J. Wysocki <[email protected]>
---
 kernel/power/disk.c |   15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)
kernel/power/disk.c +13 -2
Index: linux-2.6.22-rc2/kernel/power/disk.c
===================================================================
@@ -205,12 +205,23 @@ int hibernation_restore(int platform_mod
 
 int hibernation_platform_enter(void)
 {
+	int error;
+
 	if (hibernation_ops) {
 		kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
-		return hibernation_ops->enter();
+		/*
+		 * We have cancelled the power transition by running
+		 * hibernation_ops->finish() before saving the image, so we
+		 * should let the firmware know that we're going to enter the
+		 * sleep state after all
+		 */
+		error = hibernation_ops->prepare();
+		if (!error)
+			error = hibernation_ops->enter();
 	} else {
-		return -ENOSYS;
+		error = -ENOSYS;
 	}
+	return error;
 }
 
 /**