diff --git a/media/libmedia/AudioEffect.cpp b/media/libmedia/AudioEffect.cpp
index 3cdf48a..0f3e245 100644
--- a/media/libmedia/AudioEffect.cpp
+++ b/media/libmedia/AudioEffect.cpp
@@ -218,7 +218,7 @@
            return mIEffect->disable();
         }
     }
-    return INVALID_OPERATION;
+    return NO_ERROR;
 }
 
 status_t AudioEffect::command(uint32_t cmdCode,
@@ -231,7 +231,22 @@
         return INVALID_OPERATION;
     }
 
-    return mIEffect->command(cmdCode, cmdSize, cmdData, replySize, replyData);
+    status_t status = mIEffect->command(cmdCode, cmdSize, cmdData, replySize, replyData);
+    if (status != NO_ERROR) {
+        return status;
+    }
+    status = *(status_t *)replyData;
+    if (status != NO_ERROR) {
+        return status;
+    }
+
+    if (cmdCode == EFFECT_CMD_ENABLE) {
+        android_atomic_or(1, &mEnabled);
+    }
+    if (cmdCode == EFFECT_CMD_DISABLE) {
+        android_atomic_and(~1, &mEnabled);
+    }
+    return status;
 }
 
 
@@ -347,7 +362,11 @@
 {
     LOGV("enableStatusChanged %p enabled %d mCbf %p", this, enabled, mCbf);
     if (mStatus == ALREADY_EXISTS) {
-        mEnabled = enabled;
+        if (enabled) {
+            android_atomic_or(1, &mEnabled);
+        } else {
+            android_atomic_and(~1, &mEnabled);
+        }
         if (mCbf) {
             mCbf(EVENT_ENABLE_STATUS_CHANGED, mUserData, &enabled);
         }
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 252b42a..1c7faa4 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -1696,7 +1696,10 @@
     // Delegate master volume control to effect in output mix effect chain if needed
     sp<EffectChain> chain = getEffectChain_l(AudioSystem::SESSION_OUTPUT_MIX);
     if (chain != 0) {
-        uint32_t v = (uint32_t)(masterVolume * (1 << 24));
+        uint32_t v = 0;
+        if (!masterMute) {
+            v = (uint32_t)(masterVolume * (1 << 24));
+        }
         chain->setVolume_l(&v, &v);
         masterVolume = (float)((v + (1 << 23)) >> 24);
         chain.clear();
@@ -1750,7 +1753,7 @@
 
             // compute volume for this track
             int16_t left, right, aux;
-            if (track->isMuted() || masterMute || track->isPausing() ||
+            if (track->isMuted() || track->isPausing() ||
                 mStreamTypes[track->type()].mute) {
                 left = right = aux = 0;
                 if (track->isPausing()) {
@@ -5351,7 +5354,7 @@
         return;
     }
 
-    if (mState == ACTIVE || mState == STOPPING || mState == STOPPED) {
+    if (mState == ACTIVE || mState == STOPPING || mState == STOPPED || mState == RESTART) {
         // do 32 bit to 16 bit conversion for auxiliary effect input buffer
         if ((mDescriptor.flags & EFFECT_FLAG_TYPE_MASK) == EFFECT_FLAG_TYPE_AUXILIARY) {
             AudioMixer::ditherAndClamp(mConfig.inputCfg.buffer.s32,
@@ -6032,8 +6035,8 @@
 AudioFlinger::EffectChain::EffectChain(const wp<ThreadBase>& wThread,
                                         int sessionId)
     : mThread(wThread), mSessionId(sessionId), mActiveTrackCnt(0), mOwnInBuffer(false),
-            mVolumeCtrlIdx(-1), mLeftVolume(0), mRightVolume(0),
-            mNewLeftVolume(0), mNewRightVolume(0)
+            mVolumeCtrlIdx(-1), mLeftVolume(UINT_MAX), mRightVolume(UINT_MAX),
+            mNewLeftVolume(UINT_MAX), mNewRightVolume(UINT_MAX)
 {
     mStrategy = AudioSystem::getStrategyForStream(AudioSystem::MUSIC);
 }