diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index c995db4..6f49c7a 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2769,6 +2769,19 @@
 void SurfaceFlinger::updateInputWindowInfo() {
     std::vector<InputWindowInfo> inputHandles;
 
+    // We use a simple caching algorithm here. mInputDirty begins as true,
+    // after we call setInputWindows we set it to false, so
+    // in the future we wont call it again.. We set input dirty to true again
+    // when any layer that hasInput() has a transaction performed on it
+    // or when any parent or relative parent of such a layer has a transaction
+    // performed on it. Not all of these transactions will really result in
+    // input changes but all input changes will spring from these transactions
+    // so the cache is safe but not optimal. It seems like it might be annoyingly
+    // costly to cache and comapre the actual InputWindowHandle vector though.
+    if (!mInputDirty) {
+        return;
+    }
+
     mDrawingState.traverseInReverseZOrder([&](Layer* layer) {
         if (layer->hasInput()) {
             // When calculating the screen bounds we ignore the transparent region since it may
@@ -2780,6 +2793,8 @@
     mInputFlinger->setInputWindows(inputHandles,
                                    mInputWindowCommands.syncInputWindows ? mSetInputWindowsListener
                                                                          : nullptr);
+
+    mInputDirty = false;
 }
 
 void SurfaceFlinger::commitInputWindowCommands() {