Merge "Don't cache suspend_control service" am: 1371e73894

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1360077

Change-Id: I83bcaf82bd7a53f97112daf043c75601c99ffa34

core/java/com/android/internal/os/KernelWakelockReader.java

@@ -152,21 +152,34 @@ public class KernelWakelockReader {
         }
     }
 
+    /**
+     * Attempt to wait for suspend_control service if not immediately available.
+     */
+    private ISuspendControlService waitForSuspendControlService() throws ServiceNotFoundException {
+        final String name = "suspend_control";
+        final int numRetries = 5;
+        for (int i = 0; i < numRetries; i++) {
+            mSuspendControlService = ISuspendControlService.Stub.asInterface(
+                                        ServiceManager.getService(name));
+            if (mSuspendControlService != null) {
+                return mSuspendControlService;
+            }
+        }
+        throw new ServiceNotFoundException(name);
+    }
+
     /**
      * On success, returns the updated stats from SystemSupend, else returns null.
      */
     private KernelWakelockStats getWakelockStatsFromSystemSuspend(
             final KernelWakelockStats staleStats) {
         WakeLockInfo[] wlStats = null;
-        if (mSuspendControlService == null) {
         try {
-                mSuspendControlService = ISuspendControlService.Stub.asInterface(
+            mSuspendControlService = waitForSuspendControlService();
-                    ServiceManager.getServiceOrThrow("suspend_control"));
         } catch (ServiceNotFoundException e) {
             Slog.wtf(TAG, "Required service suspend_control not available", e);
             return null;
         }
-        }
 
         try {
             wlStats = mSuspendControlService.getWakeLockStats();