diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 65266b0..062bad6 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -361,11 +361,6 @@
                 virtual uint32_t getStrategyForSession_l(audio_session_t sessionId __unused)
                         { return 0; }
 
-                // suspend or restore effect according to the type of effect passed. a NULL
-                // type pointer means suspend all effects in the session
-                void setEffectSuspended(const effect_uuid_t *type,
-                                        bool suspend,
-                                        audio_session_t sessionId = AUDIO_SESSION_OUTPUT_MIX);
                 // check if some effects must be suspended/restored when an effect is enabled
                 // or disabled
                 void checkSuspendOnEffectEnabled(const sp<EffectModule>& effect,
@@ -417,10 +412,13 @@
                 void        releaseWakeLock_l();
                 void        updateWakeLockUids_l(const SortedVector<uid_t> &uids);
                 void        getPowerManager_l();
+                // suspend or restore effects of the specified type (or all if type is NULL)
+                // on a given session. The number of suspend requests is counted and restore
+                // occurs when all suspend requests are cancelled.
                 void setEffectSuspended_l(const effect_uuid_t *type,
                                           bool suspend,
                                           audio_session_t sessionId);
-                // updated mSuspendedSessions when an effect suspended or restored
+                // updated mSuspendedSessions when an effect is suspended or restored
                 void        updateSuspendedSessions_l(const effect_uuid_t *type,
                                                       bool suspend,
                                                       audio_session_t sessionId);
@@ -484,6 +482,7 @@
                 const sp<PMDeathRecipient> mDeathRecipient;
                 // list of suspended effects per session and per type. The first (outer) vector is
                 // keyed by session ID, the second (inner) by type UUID timeLow field
+                // Updated by updateSuspendedSessions_l() only.
                 KeyedVector< audio_session_t, KeyedVector< int, sp<SuspendedSessionDesc> > >
                                         mSuspendedSessions;
                 static const size_t     kLogSize = 4 * 1024;
@@ -1387,6 +1386,8 @@
                         }
     virtual bool        isOutput() const override { return false; }
 
+            void        checkBtNrec();
+
 private:
             // Enter standby if not already in standby, and set mStandby flag
             void    standbyIfNotAlreadyInStandby();
@@ -1394,6 +1395,8 @@
             // Call the HAL standby method unconditionally, and don't change mStandby flag
             void    inputStandBy();
 
+            void    checkBtNrec_l();
+
             AudioStreamIn                       *mInput;
             SortedVector < sp<RecordTrack> >    mTracks;
             // mActiveTracks has dual roles:  it indicates the current active track(s), and
@@ -1453,6 +1456,8 @@
             sp<NBLog::Writer>                   mFastCaptureNBLogWriter;
 
             bool                                mFastTrackAvail;    // true if fast track available
+            // common state to all record threads
+            std::atomic_bool                    mBtNrecSuspended;
 };
 
 class MmapThread : public ThreadBase