[PATCH] fix swsusp on machines not supporting S4

Fix swsusp on machines not supporting S4.  With recent changes, it is not
possible to trigger it using /sys filesystem.  Swsusp does not really need
any support from low-level code, it is possible to reboot or halt at the
end of suspend.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 16 insertions, 5 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 6ee2cad530e8..d253f3ae2fa5 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -24,7 +24,7 @@
 
 DECLARE_MUTEX(pm_sem);
 
-struct pm_ops * pm_ops = NULL;
+struct pm_ops *pm_ops;
 suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
 
 /**
@@ -151,6 +151,18 @@ static char *pm_states[PM_SUSPEND_MAX] = {
 #endif
 };
 
+static inline int valid_state(suspend_state_t state)
+{
+        /* Suspend-to-disk does not really need low-level support.
+         * It can work with reboot if needed. */
+        if (state == PM_SUSPEND_DISK)
+                return 1;
+
+        if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
+                return 0;
+        return 1;
+}
+
 
 /**
  *      enter_state - Do common work of entering low-power state.
@@ -167,7 +179,7 @@ static int enter_state(suspend_state_t state)
 {
         int error;
 
-        if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
+        if (!valid_state(state))
                 return -ENODEV;
         if (down_trylock(&pm_sem))
                 return -EBUSY;
@@ -238,9 +250,8 @@ static ssize_t state_show(struct subsystem * subsys, char * buf)
         char * s = buf;
 
         for (i = 0; i < PM_SUSPEND_MAX; i++) {
-                if (pm_states[i] && pm_ops && (!pm_ops->valid
-                        ||(pm_ops->valid && pm_ops->valid(i))))
-                        s += sprintf(s,"%s ",pm_states[i]);
+                if (pm_states[i] && valid_state(i))
+                        s += sprintf(s,"%s ", pm_states[i]);
         }
         s += sprintf(s,"\n");
         return (s - buf);