Merge branch 'pm-cpuidle' into pm-sleep

5 files changed, 62 insertions, 39 deletions

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 8236746e46bb..cb7019977c50 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -32,6 +32,7 @@ LIST_HEAD(cpuidle_detected_devices);
 static int enabled_devices;
 static int off __read_mostly;
 static int initialized __read_mostly;
+static bool use_deepest_state __read_mostly;
 
 int cpuidle_disabled(void)
 {
@@ -65,23 +66,42 @@ int cpuidle_play_dead(void)
 }
 
 /**
- * cpuidle_enabled - check if the cpuidle framework is ready
- * @dev: cpuidle device for this cpu
- * @drv: cpuidle driver for this cpu
+ * cpuidle_use_deepest_state - Enable/disable the "deepest idle" mode.
+ * @enable: Whether enable or disable the feature.
+ *
+ * If the "deepest idle" mode is enabled, cpuidle will ignore the governor and
+ * always use the state with the greatest exit latency (out of the states that
+ * are not disabled).
  *
- * Return 0 on success, otherwise:
- * -NODEV : the cpuidle framework is not available
- * -EBUSY : the cpuidle framework is not initialized
+ * This function can only be called after cpuidle_pause() to avoid races.
  */
-int cpuidle_enabled(struct cpuidle_driver *drv, struct cpuidle_device *dev)
+void cpuidle_use_deepest_state(bool enable)
 {
-        if (off || !initialized)
-                return -ENODEV;
+        use_deepest_state = enable;
+}
 
-        if (!drv || !dev || !dev->enabled)
-                return -EBUSY;
+/**
+ * cpuidle_find_deepest_state - Find the state of the greatest exit latency.
+ * @drv: cpuidle driver for a given CPU.
+ * @dev: cpuidle device for a given CPU.
+ */
+static int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
+                                      struct cpuidle_device *dev)
+{
+        unsigned int latency_req = 0;
+        int i, ret = CPUIDLE_DRIVER_STATE_START - 1;
 
-        return 0;
+        for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
+                struct cpuidle_state *s = &drv->states[i];
+                struct cpuidle_state_usage *su = &dev->states_usage[i];
+
+                if (s->disabled || su->disable || s->exit_latency <= latency_req)
+                        continue;
+
+                latency_req = s->exit_latency;
+                ret = i;
+        }
+        return ret;
 }
 
 /**
@@ -138,6 +158,15 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
  */
 int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 {
+        if (off || !initialized)
+                return -ENODEV;
+
+        if (!drv || !dev || !dev->enabled)
+                return -EBUSY;
+
+        if (unlikely(use_deepest_state))
+                return cpuidle_find_deepest_state(drv, dev);
+
         return cpuidle_curr_governor->select(drv, dev);
 }
 
@@ -169,7 +198,7 @@ int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
  */
 void cpuidle_reflect(struct cpuidle_device *dev, int index)
 {
-        if (cpuidle_curr_governor->reflect)
+        if (cpuidle_curr_governor->reflect && !unlikely(use_deepest_state))
                 cpuidle_curr_governor->reflect(dev, index);
 }
 
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 71b523293354..c4f80c15a48d 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -296,7 +296,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
                 data->needs_update = 0;
         }
 
-        data->last_state_idx = 0;
+        data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1;
 
         /* Special case when user has set very strict latency requirement */
         if (unlikely(latency_req == 0))
@@ -311,13 +311,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
         data->bucket = which_bucket(data->next_timer_us);
 
         /*
-         * if the correction factor is 0 (eg first time init or cpu hotplug
-         * etc), we actually want to start out with a unity factor.
-         */
-        if (data->correction_factor[data->bucket] == 0)
-                data->correction_factor[data->bucket] = RESOLUTION * DECAY;
-
-        /*
          * Force the result of multiplication to be 64 bits even if both
          * operands are 32 bits.
          * Make sure to round up for half microseconds.
@@ -466,9 +459,17 @@ static int menu_enable_device(struct cpuidle_driver *drv,
                                 struct cpuidle_device *dev)
 {
         struct menu_device *data = &per_cpu(menu_devices, dev->cpu);
+        int i;
 
         memset(data, 0, sizeof(struct menu_device));
 
+        /*
+         * if the correction factor is 0 (eg first time init or cpu hotplug
+         * etc), we actually want to start out with a unity factor.
+         */
+        for(i = 0; i < BUCKETS; i++)
+                data->correction_factor[i] = RESOLUTION * DECAY;
+
         return 0;
 }
 
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index b0238cba440b..c51a436135c4 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -120,8 +120,6 @@ struct cpuidle_driver {
 #ifdef CONFIG_CPU_IDLE
 extern void disable_cpuidle(void);
 
-extern int cpuidle_enabled(struct cpuidle_driver *drv,
-                          struct cpuidle_device *dev);
 extern int cpuidle_select(struct cpuidle_driver *drv,
                           struct cpuidle_device *dev);
 extern int cpuidle_enter(struct cpuidle_driver *drv,
@@ -145,13 +143,11 @@ extern void cpuidle_resume(void);
 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 extern int cpuidle_play_dead(void);
+extern void cpuidle_use_deepest_state(bool enable);
 
 extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 #else
 static inline void disable_cpuidle(void) { }
-static inline int cpuidle_enabled(struct cpuidle_driver *drv,
-                                  struct cpuidle_device *dev)
-{return -ENODEV; }
 static inline int cpuidle_select(struct cpuidle_driver *drv,
                                  struct cpuidle_device *dev)
 {return -ENODEV; }
@@ -180,6 +176,7 @@ static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 {return -ENODEV; }
 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 static inline int cpuidle_play_dead(void) {return -ENODEV; }
+static inline void cpuidle_use_deepest_state(bool enable) {}
 static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
         struct cpuidle_device *dev) {return NULL; }
 #endif
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 8233cd4047d7..155721f7f909 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -54,9 +54,11 @@ static void freeze_begin(void)
 
 static void freeze_enter(void)
 {
+        cpuidle_use_deepest_state(true);
         cpuidle_resume();
         wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
         cpuidle_pause();
+        cpuidle_use_deepest_state(false);
 }
 
 void freeze_wake(void)
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 8f4390a079c7..a8f12247ce7c 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -101,19 +101,13 @@ static int cpuidle_idle_call(void)
         rcu_idle_enter();
 
         /*
-         * Check if the cpuidle framework is ready, otherwise fallback
-         * to the default arch specific idle method
+         * Ask the cpuidle framework to choose a convenient idle state.
+         * Fall back to the default arch specific idle method on errors.
          */
-        ret = cpuidle_enabled(drv, dev);
-
-        if (!ret) {
-                /*
-                 * Ask the governor to choose an idle state it thinks
-                 * it is convenient to go to. There is *always* a
-                 * convenient idle state
-                 */
-                next_state = cpuidle_select(drv, dev);
+        next_state = cpuidle_select(drv, dev);
 
+        ret = next_state;
+        if (ret >= 0) {
                 /*
                  * The idle task must be scheduled, it is pointless to
                  * go to idle, just update no idle residency and get
@@ -140,7 +134,7 @@ static int cpuidle_idle_call(void)
                                         CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
                                         &dev->cpu);
 
-                        if (!ret) {
+                        if (ret >= 0) {
                                 trace_cpu_idle_rcuidle(next_state, dev->cpu);
 
                                 /*
@@ -175,7 +169,7 @@ static int cpuidle_idle_call(void)
          * We can't use the cpuidle framework, let's use the default
          * idle routine
          */
-        if (ret)
+        if (ret < 0)
                 arch_cpu_idle();
 
         __current_set_polling();