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, 18 insertions, 8 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index cfba6987ae7d..350b485b3b60 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -25,11 +25,13 @@
 
 BLOCKING_NOTIFIER_HEAD(pm_chain_head);
 
-/*This is just an arbitrary number */
-#define FREE_PAGE_NUMBER (100)
-
 DEFINE_MUTEX(pm_mutex);
 
+#ifdef CONFIG_SUSPEND
+
+/* This is just an arbitrary number */
+#define FREE_PAGE_NUMBER (100)
+
 struct pm_ops *pm_ops;
 
 /**
@@ -269,6 +271,8 @@ int pm_suspend(suspend_state_t state)
 
 EXPORT_SYMBOL(pm_suspend);
 
+#endif /* CONFIG_SUSPEND */
+
 decl_subsys(power,NULL,NULL);
 
 
@@ -285,13 +289,15 @@ decl_subsys(power,NULL,NULL);
 
 static ssize_t state_show(struct kset *kset, char *buf)
 {
+        char *s = buf;
+#ifdef CONFIG_SUSPEND
         int i;
-        char * s = buf;
 
         for (i = 0; i < PM_SUSPEND_MAX; i++) {
                 if (pm_states[i] && valid_state(i))
                         s += sprintf(s,"%s ", pm_states[i]);
         }
+#endif
 #ifdef CONFIG_HIBERNATION
         s += sprintf(s, "%s\n", "disk");
 #else
@@ -304,11 +310,13 @@ static ssize_t state_show(struct kset *kset, char *buf)
 
 static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
 {
+#ifdef CONFIG_SUSPEND
         suspend_state_t state = PM_SUSPEND_STANDBY;
         const char * const *s;
+#endif
         char *p;
-        int error;
         int len;
+        int error = -EINVAL;
 
         p = memchr(buf, '\n', n);
         len = p ? p - buf : n;
@@ -316,17 +324,19 @@ static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
         /* First, check if we are requested to hibernate */
         if (len == 4 && !strncmp(buf, "disk", len)) {
                 error = hibernate();
-                return error ? error : n;
+  goto Exit;
         }
 
+#ifdef CONFIG_SUSPEND
         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
                         break;
         }
         if (state < PM_SUSPEND_MAX && *s)
                 error = enter_state(state);
-        else
-                error = -EINVAL;
+#endif
+
+ Exit:
         return error ? error : n;
 }