PM / sleep: Asynchronous threads for suspend_late

In analogy with commits 5af84b82701a and 97df8c12995, using
asynchronous threads can improve the overall suspend_late
time significantly.

This patch is for suspend_late phase.

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 54 insertions, 12 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 9335b326d1f5..42355e442a5d 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1127,16 +1127,26 @@ static int dpm_suspend_noirq(pm_message_t state)
  *
  * Runtime PM is disabled for @dev while this function is being executed.
  */
-static int device_suspend_late(struct device *dev, pm_message_t state)
+static int __device_suspend_late(struct device *dev, pm_message_t state, bool async)
 {
         pm_callback_t callback = NULL;
         char *info = NULL;
-        int error;
+        int error = 0;
 
         __pm_runtime_disable(dev, false);
 
+        if (async_error)
+                goto Complete;
+
+        if (pm_wakeup_pending()) {
+                async_error = -EBUSY;
+                goto Complete;
+        }
+
         if (dev->power.syscore)
-                return 0;
+                goto Complete;
+
+        dpm_wait_for_children(dev, async);
 
         if (dev->pm_domain) {
                 info = "late power domain ";
@@ -1160,10 +1170,40 @@ static int device_suspend_late(struct device *dev, pm_message_t state)
         error = dpm_run_callback(callback, dev, state, info);
         if (!error)
                 dev->power.is_late_suspended = true;
+        else
+                async_error = error;
 
+Complete:
+        complete_all(&dev->power.completion);
         return error;
 }
 
+static void async_suspend_late(void *data, async_cookie_t cookie)
+{
+        struct device *dev = (struct device *)data;
+        int error;
+
+        error = __device_suspend_late(dev, pm_transition, true);
+        if (error) {
+                dpm_save_failed_dev(dev_name(dev));
+                pm_dev_err(dev, pm_transition, " async", error);
+        }
+        put_device(dev);
+}
+
+static int device_suspend_late(struct device *dev)
+{
+        reinit_completion(&dev->power.completion);
+
+        if (pm_async_enabled && dev->power.async_suspend) {
+                get_device(dev);
+                async_schedule(async_suspend_late, dev);
+                return 0;
+        }
+
+        return __device_suspend_late(dev, pm_transition, false);
+}
+
 /**
  * dpm_suspend_late - Execute "late suspend" callbacks for all devices.
  * @state: PM transition of the system being carried out.
@@ -1174,19 +1214,20 @@ static int dpm_suspend_late(pm_message_t state)
         int error = 0;
 
         mutex_lock(&dpm_list_mtx);
+        pm_transition = state;
+        async_error = 0;
+
         while (!list_empty(&dpm_suspended_list)) {
                 struct device *dev = to_device(dpm_suspended_list.prev);
 
                 get_device(dev);
                 mutex_unlock(&dpm_list_mtx);
 
-                error = device_suspend_late(dev, state);
+                error = device_suspend_late(dev);
 
                 mutex_lock(&dpm_list_mtx);
                 if (error) {
                         pm_dev_err(dev, state, " late", error);
-                        suspend_stats.failed_suspend_late++;
-                        dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
                         dpm_save_failed_dev(dev_name(dev));
                         put_device(dev);
                         break;
@@ -1195,17 +1236,18 @@ static int dpm_suspend_late(pm_message_t state)
                         list_move(&dev->power.entry, &dpm_late_early_list);
                 put_device(dev);
 
-                if (pm_wakeup_pending()) {
-                        error = -EBUSY;
+                if (async_error)
                         break;
-                }
         }
         mutex_unlock(&dpm_list_mtx);
-        if (error)
+        async_synchronize_full();
+        if (error) {
+                suspend_stats.failed_suspend_late++;
+                dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
                 dpm_resume_early(resume_event(state));
-        else
+        } else {
                 dpm_show_time(starttime, state, "late");
-
+        }
         return error;
 }