Introduce CONFIG_SUSPEND for suspend-to-Ram and standby

Introduce CONFIG_SUSPEND representing the ability to enter system sleep
states, such as the ACPI S3 state, and allow the user to choose SUSPEND
and HIBERNATION independently of each other.

Make HOTPLUG_CPU be selected automatically if SUSPEND or HIBERNATION has
been chosen and the kernel is intended for SMP systems.

Also, introduce CONFIG_PM_SLEEP which is automatically selected if
CONFIG_SUSPEND or CONFIG_HIBERNATION is set and use it to select the
code needed for both suspend and hibernation.

The top-level power management headers and the ACPI code related to
suspend and hibernation are modified to use the new definitions (the
changes in drivers/acpi/sleep/main.c are, mostly, moving code to reduce
the number of ifdefs).

There are many other files in which CONFIG_PM can be replaced with
CONFIG_PM_SLEEP or even with CONFIG_SUSPEND, but they can be updated in
the future.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/kernel/power/power.h b/kernel/power/power.h
index 9080914796f5..95fbf2dd3fe3 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -176,9 +176,17 @@ struct timeval;
 extern void swsusp_show_speed(struct timeval *, struct timeval *,
                                 unsigned int, char *);
 
+#ifdef CONFIG_SUSPEND
 /* kernel/power/main.c */
-extern int suspend_enter(suspend_state_t state);
 extern int suspend_devices_and_enter(suspend_state_t state);
+#else /* !CONFIG_SUSPEND */
+static inline int suspend_devices_and_enter(suspend_state_t state)
+{
+        return -ENOSYS;
+}
+#endif /* !CONFIG_SUSPEND */
+
+/* kernel/power/common.c */
 extern struct blocking_notifier_head pm_chain_head;
 
 static inline int pm_notifier_call_chain(unsigned long val)