diff --git a/services/surfaceflinger/Android.mk b/services/surfaceflinger/Android.mk
index f279491f5..183478d65 100644
--- a/services/surfaceflinger/Android.mk
+++ b/services/surfaceflinger/Android.mk
@@ -83,7 +83,7 @@ else
     LOCAL_CFLAGS += -DPRESENT_TIME_OFFSET_FROM_VSYNC_NS=0
 endif
 
-LOCAL_CFLAGS += -fvisibility=hidden
+LOCAL_CFLAGS += -fvisibility=hidden -Werror=format
 LOCAL_CFLAGS += -std=c++11
 
 LOCAL_SHARED_LIBRARIES := \
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 6a034ecdc..63ee4e36e 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -637,10 +637,16 @@ status_t SurfaceFlinger::setActiveConfig(const sp<IBinder>& display, int mode) {
                                int mode) :
             mFlinger(flinger), mDisplay(disp) { mMode = mode; }
         virtual bool handler() {
+            Vector<DisplayInfo> configs;
+            mFlinger.getDisplayConfigs(mDisplay, &configs);
+            if(mMode < 0 || mMode >= configs.size()) {
+                ALOGE("Attempt to set active config = %d for display with %d configs",
+                        mMode, configs.size());
+            }
             sp<DisplayDevice> hw(mFlinger.getDisplayDevice(mDisplay));
             if (hw == NULL) {
                 ALOGE("Attempt to set active config = %d for null display %p",
-                        mDisplay.get(), mMode);
+                        mMode, mDisplay.get());
             } else if (hw->getDisplayType() >= DisplayDevice::DISPLAY_VIRTUAL) {
                 ALOGW("Attempt to set active config = %d for virtual display",
                         mMode);
@@ -2267,7 +2273,7 @@ void SurfaceFlinger::setPowerMode(const sp<IBinder>& display, int mode) {
             sp<DisplayDevice> hw(mFlinger.getDisplayDevice(mDisplay));
             if (hw == NULL) {
                 ALOGE("Attempt to set power mode = %d for null display %p",
-                        mDisplay.get(), mMode);
+                        mMode, mDisplay.get());
             } else if (hw->getDisplayType() >= DisplayDevice::DISPLAY_VIRTUAL) {
                 ALOGW("Attempt to set power mode = %d for virtual display",
                         mMode);