PowerManagerService: open power HAL less aggressively

Once the power HAL has failed to open once, don't try to open it again
on subsequent calls to the service.

Test: remove power HAL on marlin & confirm log spam stops.
Bug: 38028137
Change-Id: If7bc4f7080e8822b68da0d1bd81df8de1ce388aa
Signed-off-by: Connor O'Brien <connoro@google.com>

services/core/jni/com_android_server_power_PowerManagerService.cpp

@@ -57,6 +57,7 @@ static struct {
 
 static jobject gPowerManagerServiceObj;
 sp<IPower> gPowerHal = nullptr;
+bool gPowerHalExists = true;
 std::mutex gPowerHalMutex;
 static nsecs_t gLastEventTime[USER_ACTIVITY_EVENT_LAST + 1];
 
@@ -78,12 +79,13 @@ static bool checkAndClearExceptionFromCallback(JNIEnv* env, const char* methodNa
 // Check validity of current handle to the power HAL service, and call getService() if necessary.
 // The caller must be holding gPowerHalMutex.
 bool getPowerHal() {
-    if (gPowerHal == nullptr) {
+    if (gPowerHalExists && gPowerHal == nullptr) {
         gPowerHal = IPower::getService();
         if (gPowerHal != nullptr) {
             ALOGI("Loaded power HAL service");
         } else {
             ALOGI("Couldn't load power HAL service");
+            gPowerHalExists = false;
         }
     }
     return gPowerHal != nullptr;