diff --git a/quickstep/src/com/android/quickstep/TouchInteractionService.java b/quickstep/src/com/android/quickstep/TouchInteractionService.java
index 5b085d2185..fcc512119f 100644
--- a/quickstep/src/com/android/quickstep/TouchInteractionService.java
+++ b/quickstep/src/com/android/quickstep/TouchInteractionService.java
@@ -74,6 +74,7 @@ import android.view.MotionEvent;
 import android.view.View;
 
 import androidx.annotation.BinderThread;
+import androidx.annotation.MainThread;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.UiThread;
@@ -550,11 +551,15 @@ public class TouchInteractionService extends Service {
                 @Override
                 public void onInputDeviceAdded(int deviceId) {
                     if (isTrackpadDevice(deviceId)) {
-                        boolean wasEmpty = mTrackpadsConnected.isEmpty();
-                        mTrackpadsConnected.add(deviceId);
-                        if (wasEmpty) {
-                            update();
-                        }
+                        // This updates internal TIS state so it needs to also run on the main
+                        // thread.
+                        MAIN_EXECUTOR.execute(() -> {
+                            boolean wasEmpty = mTrackpadsConnected.isEmpty();
+                            mTrackpadsConnected.add(deviceId);
+                            if (wasEmpty) {
+                                update();
+                            }
+                        });
                     }
                 }
 
@@ -564,12 +569,17 @@ public class TouchInteractionService extends Service {
 
                 @Override
                 public void onInputDeviceRemoved(int deviceId) {
-                    mTrackpadsConnected.remove(deviceId);
-                    if (mTrackpadsConnected.isEmpty()) {
-                        update();
-                    }
+                    // This updates internal TIS state so it needs to also run on the main
+                    // thread.
+                    MAIN_EXECUTOR.execute(() -> {
+                        mTrackpadsConnected.remove(deviceId);
+                        if (mTrackpadsConnected.isEmpty()) {
+                            update();
+                        }
+                    });
                 }
 
+                @MainThread
                 private void update() {
                     if (mInputMonitorCompat != null && !mTrackpadsConnected.isEmpty()) {
                         // Don't destroy and reinitialize input monitor due to trackpad
@@ -580,6 +590,7 @@ public class TouchInteractionService extends Service {
                 }
 
                 private boolean isTrackpadDevice(int deviceId) {
+                    // This is a blocking binder call that should run on a bg thread.
                     InputDevice inputDevice = mInputManager.getInputDevice(deviceId);
                     if (inputDevice == null) {
                         return false;