PM / hibernate: no kernel_power_off when pm_power_off NULL

Reboot logic in kernel/reboot will avoid calling kernel_power_off
when pm_power_off is null, and instead uses kernel_halt.  Change
hibernate's power_down to follow the behavior in the reboot call.

Calling the notifier twice (once for SYS_POWER_OFF and again for
SYS_HALT) causes a panic during hibernation on Kirkwood
Openblocks A6 board.

Signed-off-by: Sebastian Capella <sebastian.capella@linaro.org>
Reported-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index de4b989cc8fd..1f08ac7f55d8 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -599,7 +599,8 @@ static void power_down(void)
         case HIBERNATION_PLATFORM:
                 hibernation_platform_enter();
         case HIBERNATION_SHUTDOWN:
-                kernel_power_off();
+                if (pm_power_off)
+                        kernel_power_off();
                 break;
 #ifdef CONFIG_SUSPEND
         case HIBERNATION_SUSPEND:
@@ -627,7 +628,8 @@ static void power_down(void)
          * corruption after resume.
          */
         printk(KERN_CRIT "PM: Please power down manually\n");
-        while(1);
+        while (1)
+                cpu_relax();
 }
 
 /**