Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux...

[linux-2.6-microblaze.git] / kernel / sched / idle.c

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index aaf1c1d..94b2d7b 100644 (file)
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -7,6 +7,7 @@
 #include <linux/tick.h>
 #include <linux/mm.h>
 #include <linux/stackprotector.h>
+#include <linux/suspend.h>
 
 #include <asm/tlb.h>
 
@@ -104,6 +105,21 @@ static void cpuidle_idle_call(void)
         */
        rcu_idle_enter();
 
+       /*
+        * Suspend-to-idle ("freeze") is a system state in which all user space
+        * has been frozen, all I/O devices have been suspended and the only
+        * activity happens here and in iterrupts (if any).  In that case bypass
+        * the cpuidle governor and go stratight for the deepest idle state
+        * available.  Possibly also suspend the local tick and the entire
+        * timekeeping to prevent timer interrupts from kicking us out of idle
+        * until a proper wakeup interrupt happens.
+        */
+       if (idle_should_freeze()) {
+               cpuidle_enter_freeze();
+               local_irq_enable();
+               goto exit_idle;
+       }
+
        /*
         * Ask the cpuidle framework to choose a convenient idle state.
         * Fall back to the default arch idle method on errors.