diff --git a/power/aidl/aidl_api/android.hardware.power/current/android/hardware/power/ChannelMessage.aidl b/power/aidl/aidl_api/android.hardware.power/current/android/hardware/power/ChannelMessage.aidl
index 25f01c0..ab38fcc 100644
--- a/power/aidl/aidl_api/android.hardware.power/current/android/hardware/power/ChannelMessage.aidl
+++ b/power/aidl/aidl_api/android.hardware.power/current/android/hardware/power/ChannelMessage.aidl
@@ -35,10 +35,11 @@
 @FixedSize @VintfStability
 parcelable ChannelMessage {
   int sessionID;
+  long timeStampNanos;
   android.hardware.power.ChannelMessage.ChannelMessageContents data;
   @FixedSize @VintfStability
   union ChannelMessageContents {
-    int[20] tids = {(-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */, (-1) /* -1 */};
+    long[16] reserved = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
     long targetDuration;
     android.hardware.power.SessionHint hint;
     android.hardware.power.ChannelMessage.ChannelMessageContents.SessionModeSetter mode;
diff --git a/power/aidl/aidl_api/android.hardware.power/current/android/hardware/power/WorkDurationFixedV1.aidl b/power/aidl/aidl_api/android.hardware.power/current/android/hardware/power/WorkDurationFixedV1.aidl
index 8cd246d..45310b8 100644
--- a/power/aidl/aidl_api/android.hardware.power/current/android/hardware/power/WorkDurationFixedV1.aidl
+++ b/power/aidl/aidl_api/android.hardware.power/current/android/hardware/power/WorkDurationFixedV1.aidl
@@ -34,7 +34,6 @@
 package android.hardware.power;
 @FixedSize @VintfStability
 parcelable WorkDurationFixedV1 {
-  long timeStampNanos;
   long durationNanos;
   long workPeriodStartTimestampNanos;
   long cpuDurationNanos;
diff --git a/power/aidl/android/hardware/power/ChannelMessage.aidl b/power/aidl/android/hardware/power/ChannelMessage.aidl
index 4747d90..fa16911 100644
--- a/power/aidl/android/hardware/power/ChannelMessage.aidl
+++ b/power/aidl/android/hardware/power/ChannelMessage.aidl
@@ -38,6 +38,12 @@
     int sessionID;
 
     /**
+     * Timestamp in nanoseconds based on CLOCK_MONOTONIC when the message was sent,
+     * used to ensure all messages can be processed in a coherent order.
+     */
+    long timeStampNanos;
+
+    /**
      * A union defining the different messages that can be passed through the
      * channel. Each type corresponds to a different call in IPowerHintSession.
      */
@@ -47,12 +53,9 @@
     @VintfStability
     union ChannelMessageContents {
         /**
-         * List of TIDs for this session to change to. Can be used in cases
-         * where HintManagerService is not needed to validate the TIDs, such as
-         * when all TIDs directly belong to the process that owns the session.
+         * Reserves the maximum fixed size for the ChannelMessage.
          */
-        int[20] tids = {
-                -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1};
+        long[16] reserved = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 
         /**
          * Setting this field will update the session’s target duration, equivalent
diff --git a/power/aidl/android/hardware/power/WorkDurationFixedV1.aidl b/power/aidl/android/hardware/power/WorkDurationFixedV1.aidl
index 2d202ff..ef5c755 100644
--- a/power/aidl/android/hardware/power/WorkDurationFixedV1.aidl
+++ b/power/aidl/android/hardware/power/WorkDurationFixedV1.aidl
@@ -20,12 +20,6 @@
 @VintfStability
 parcelable WorkDurationFixedV1 {
     /**
-     * Timestamp in nanoseconds based on CLOCK_MONOTONIC when the duration
-     * sample was measured.
-     */
-    long timeStampNanos;
-
-    /**
      * Total work duration in nanoseconds.
      */
     long durationNanos;