Hibernation: Check if ACPI is enabled during restore in the right place

The following scenario leads to total confusion of the platform firmware on
some boxes (eg. HPC nx6325):
* Hibernate with ACPI enabled
* Resume passing "acpi=off" to the boot kernel

To prevent this from happening it's necessary to check if ACPI is enabled (and
enable it if that's not the case) _right_ _after_ control has been transfered
from the boot kernel to the image kernel, before device_power_up() is called
(ie.  with interrupts disabled).   Enabling ACPI after calling
device_power_up() turns out to be insufficient.

For this reason, introduce new hibernation callback ->leave() that will be
executed before device_power_up() by the restored image kernel.   To make it
work, it also is necessary to move swsusp_suspend() from swsusp.c to disk.c
(it's name is changed to "create_image", which is more up to the point).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 9fd2b9acf7d..4360e081695 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -156,6 +156,12 @@ extern void mark_free_pages(struct zone *zone);
  *      Called after the nonboot CPUs have been disabled and all of the low
  *      level devices have been shut down (runs with IRQs off).
  *
+ * @leave: Perform the first stage of the cleanup after the system sleep state
+ *      indicated by @set_target() has been left.
+ *      Called right after the control has been passed from the boot kernel to
+ *      the image kernel, before the nonboot CPUs are enabled and before devices
+ *      are resumed.  Executed with interrupts disabled.
+ *
  * @pre_restore: Prepare system for the restoration from a hibernation image.
  *      Called right after devices have been frozen and before the nonboot
  *      CPUs are disabled (runs with IRQs on).
@@ -170,6 +176,7 @@ struct platform_hibernation_ops {
         void (*finish)(void);
         int (*prepare)(void);
         int (*enter)(void);
+        void (*leave)(void);
         int (*pre_restore)(void);
         void (*restore_cleanup)(void);
 };