Hibernation: prepare to enter the low power state

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 <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 77ac605bf20a..885c653509c9 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -205,12 +205,23 @@ int hibernation_restore(int platform_mode)
 
 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;
 }
 
 /**