--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -1136,26 +1136,19 @@ MediaDecoderStateMachine::SetDormant(boo
 {
   MOZ_ASSERT(OnTaskQueue());
 
   if (IsShutdown()) {
     return;
   }
 
   if (mMetadataRequest.Exists()) {
-    if (mPendingDormant && mPendingDormant.ref() != aDormant && !aDormant) {
-      // We already have a dormant request pending; the new request would have
-      // resumed from dormant, we can just cancel any pending dormant requests.
-      mPendingDormant.reset();
-    } else {
-      mPendingDormant = Some(aDormant);
-    }
+    mPendingDormant = aDormant;
     return;
   }
-  mPendingDormant.reset();
 
   DECODER_LOG("SetDormant=%d", aDormant);
 
   if (aDormant) {
     if (mState == DECODER_STATE_SEEKING) {
       if (mQueuedSeek.Exists()) {
         // Keep latest seek target
       } else if (mCurrentSeek.Exists()) {
@@ -1197,17 +1190,17 @@ MediaDecoderStateMachine::SetDormant(boo
 
     // Note that we do not wait for the decode task queue to go idle before
     // queuing the ReleaseMediaResources task - instead, we disconnect promises,
     // reset state, and put a ResetDecode in the decode task queue. Any tasks
     // that run after ResetDecode are supposed to run with a clean slate. We rely
     // on that in other places (i.e. seeking), so it seems reasonable to rely on
     // it here as well.
     mReader->ReleaseMediaResources();
-  } else if ((aDormant != true) && (mState == DECODER_STATE_DORMANT)) {
+  } else if (mState == DECODER_STATE_DORMANT) {
     mDecodingFirstFrame = true;
     SetState(DECODER_STATE_DECODING_METADATA);
     ReadMetadata();
   }
 }
 
 RefPtr<ShutdownPromise>
 MediaDecoderStateMachine::Shutdown()
@@ -1971,17 +1964,18 @@ MediaDecoderStateMachine::DecodeError()
 void
 MediaDecoderStateMachine::OnMetadataRead(MetadataHolder* aMetadata)
 {
   MOZ_ASSERT(OnTaskQueue());
   MOZ_ASSERT(mState == DECODER_STATE_DECODING_METADATA);
   mMetadataRequest.Complete();
 
   if (mPendingDormant) {
-    SetDormant(mPendingDormant.ref());
+    mPendingDormant = false;
+    SetDormant(true);
     return;
   }
 
   // Set mode to PLAYBACK after reading metadata.
   mResource->SetReadMode(MediaCacheStream::MODE_PLAYBACK);
   mInfo = aMetadata->mInfo;
   mMetadataTags = aMetadata->mTags.forget();
   RefPtr<MediaDecoderStateMachine> self = this;

--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -851,18 +851,20 @@ private:
   // the state machine thread. Synchronised via decoder monitor.
   // When data is being sent to a MediaStream, this is true when all data has
   // been written to the MediaStream.
   Watchable<bool> mAudioCompleted;
 
   // True if all video frames are already rendered.
   Watchable<bool> mVideoCompleted;
 
-  // Set if MDSM receives dormant request during reading metadata.
-  Maybe<bool> mPendingDormant;
+  // True if we need to enter dormant state after reading metadata. Note that
+  // we can't enter dormant state until reading metadata is done for some
+  // limitations of the reader.
+  bool mPendingDormant = false;
 
   // Flag whether we notify metadata before decoding the first frame or after.
   //
   // Note that the odd semantics here are designed to replicate the current
   // behavior where we notify the decoder each time we come out of dormant, but
   // send suppressed event visibility for those cases. This code can probably be
   // simplified.
   bool mNotifyMetadataBeforeFirstFrame;