Modifications in audio effect engine state management.

- Separate the updating of effect engine state from the process call in EffectModule so that the state
of all effects in the same effect chain is updated simultaneusly before all process functions are called.
- Added a mechanism for the effect engine to continue being called for processing after receiving the disable
commands untils it considers that the framework can stop calling the process function without causing
a glitch or loosing some effect tail.
- Updated test reverb and equalizer to support this new feature

Change-Id: Icb56ae2c84c076d4dbad6cf733b1a62f823febe7

7 files changed, 154 insertions, 45 deletions

diff --git a/include/media/EffectApi.h b/include/media/EffectApi.h
index b4d738cc9c46..9f3d0b655203 100644
--- a/include/media/EffectApi.h
+++ b/include/media/EffectApi.h
@@ -223,6 +223,11 @@ typedef struct audio_buffer_s audio_buffer_t;
 //          samples as specified in output buffer descriptor. If the buffer descriptor
 //          is not specified the function must use either the buffer or the
 //          buffer provider function installed by the EFFECT_CMD_CONFIGURE command.
+//          The effect framework will call the process() function after the EFFECT_CMD_ENABLE
+//          command is received and until the EFFECT_CMD_DISABLE is received. When the engine
+//          receives the EFFECT_CMD_DISABLE command it should turn off the effect gracefully
+//          and when done indicate that it is OK to stop calling the process() function by
+//          returning the -ENODATA status.
 //
 //    NOTE: the process() function implementation should be "real-time safe" that is
 //      it should not perform blocking calls: malloc/free, sleep, read/write/open/close,
@@ -239,6 +244,8 @@ typedef struct audio_buffer_s audio_buffer_t;
 //
 //    Output:
 //        returned value:    0 successful operation
+//                          -ENODATA the engine has finished the disable phase and the framework
+//                                  can stop calling process()
 //                          -EINVAL invalid interface handle or
 //                                  invalid input/output buffer description
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/libs/audioflinger/AudioFlinger.cpp b/libs/audioflinger/AudioFlinger.cpp
index e6f46ce9ecc0..97eb6c09fc0b 100644
--- a/libs/audioflinger/AudioFlinger.cpp
+++ b/libs/audioflinger/AudioFlinger.cpp
@@ -17,8 +17,7 @@
 
 
 #define LOG_TAG "AudioFlinger"
-//
-#define LOG_NDEBUG 0
+//#define LOG_NDEBUG 0
 
 #include <math.h>
 #include <signal.h>
@@ -5085,15 +5084,53 @@ void AudioFlinger::EffectModule::disconnect(const wp<EffectHandle>& handle)
     }
 }
 
+void AudioFlinger::EffectModule::updateState() {
+    Mutex::Autolock _l(mLock);
+
+    switch (mState) {
+    case RESTART:
+        reset_l();
+        // FALL THROUGH
+
+    case STARTING:
+        // clear auxiliary effect input buffer for next accumulation
+        if ((mDescriptor.flags & EFFECT_FLAG_TYPE_MASK) == EFFECT_FLAG_TYPE_AUXILIARY) {
+            memset(mConfig.inputCfg.buffer.raw,
+                   0,
+                   mConfig.inputCfg.buffer.frameCount*sizeof(int32_t));
+        }
+        start_l();
+        mState = ACTIVE;
+        break;
+    case STOPPING:
+        stop_l();
+        mDisableWaitCnt = mMaxDisableWaitCnt;
+        mState = STOPPED;
+        break;
+    case STOPPED:
+        // mDisableWaitCnt is forced to 1 by process() when the engine indicates the end of the
+        // turn off sequence.
+        if (--mDisableWaitCnt == 0) {
+            reset_l();
+            mState = IDLE;
+        }
+        break;
+    default: //IDLE , ACTIVE
+        break;
+    }
+}
+
 void AudioFlinger::EffectModule::process()
 {
     Mutex::Autolock _l(mLock);
 
-    if (mEffectInterface == NULL || mConfig.inputCfg.buffer.raw == NULL || mConfig.outputCfg.buffer.raw == NULL) {
+    if (mEffectInterface == NULL ||
+            mConfig.inputCfg.buffer.raw == NULL ||
+            mConfig.outputCfg.buffer.raw == NULL) {
         return;
     }
 
-    if (mState != IDLE) {
+    if (mState == ACTIVE || mState == STOPPING || mState == STOPPED) {
         // 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,
@@ -5101,33 +5138,15 @@ void AudioFlinger::EffectModule::process()
                                         mConfig.inputCfg.buffer.frameCount);
         }
 
-        // TODO: handle effects with buffer provider
-        if (mState != ACTIVE) {
-            switch (mState) {
-            case RESET:
-                reset_l();
-                mState = STARTING;
-                // clear auxiliary effect input buffer for next accumulation
-                if ((mDescriptor.flags & EFFECT_FLAG_TYPE_MASK) == EFFECT_FLAG_TYPE_AUXILIARY) {
-                    memset(mConfig.inputCfg.buffer.raw, 0, mConfig.inputCfg.buffer.frameCount*sizeof(int32_t));
-                }
-                return;
-            case STARTING:
-                start_l();
-                mState = ACTIVE;
-                break;
-            case STOPPING:
-                mState = STOPPED;
-                break;
-            case STOPPED:
-                stop_l();
-                mState = IDLE;
-                return;
-            }
-        }
-
         // do the actual processing in the effect engine
-        (*mEffectInterface)->process(mEffectInterface, &mConfig.inputCfg.buffer, &mConfig.outputCfg.buffer);
+        int ret = (*mEffectInterface)->process(mEffectInterface,
+                                               &mConfig.inputCfg.buffer,
+                                               &mConfig.outputCfg.buffer);
+
+        // force transition to IDLE state when engine is ready
+        if (mState == STOPPED && ret == -ENODATA) {
+            mDisableWaitCnt = 1;
+        }
 
         // clear auxiliary effect input buffer for next accumulation
         if ((mDescriptor.flags & EFFECT_FLAG_TYPE_MASK) == EFFECT_FLAG_TYPE_AUXILIARY) {
@@ -5216,6 +5235,10 @@ status_t AudioFlinger::EffectModule::configure()
     if (status == 0) {
         status = cmdStatus;
     }
+
+    mMaxDisableWaitCnt = (MAX_DISABLE_TIME_MS * mConfig.outputCfg.samplingRate) /
+            (1000 * mConfig.outputCfg.buffer.frameCount);
+
     return status;
 }
 
@@ -5292,21 +5315,19 @@ status_t AudioFlinger::EffectModule::setEnabled(bool enabled)
         switch (mState) {
         // going from disabled to enabled
         case IDLE:
-            mState = RESET;
+            mState = STARTING;
+            break;
+        case STOPPED:
+            mState = RESTART;
             break;
         case STOPPING:
             mState = ACTIVE;
             break;
-        case STOPPED:
-            mState = STARTING;
-            break;
 
         // going from enabled to disabled
-        case RESET:
-            mState = IDLE;
-            break;
+        case RESTART:
         case STARTING:
-            mState = STOPPED;
+            mState = IDLE;
             break;
         case ACTIVE:
             mState = STOPPING;
@@ -5325,7 +5346,7 @@ status_t AudioFlinger::EffectModule::setEnabled(bool enabled)
 bool AudioFlinger::EffectModule::isEnabled()
 {
     switch (mState) {
-    case RESET:
+    case RESTART:
     case STARTING:
     case ACTIVE:
         return true;
@@ -5772,6 +5793,9 @@ void AudioFlinger::EffectChain::process_l()
     for (size_t i = 0; i < size; i++) {
         mEffects[i]->process();
     }
+    for (size_t i = 0; i < size; i++) {
+        mEffects[i]->updateState();
+    }
     // if no track is active, input buffer must be cleared here as the mixer process
     // will not do it
     if (mSessionId > 0 && activeTracks() == 0) {
diff --git a/libs/audioflinger/AudioFlinger.h b/libs/audioflinger/AudioFlinger.h
index ec3d7f1ba12c..507c9ac84123 100644
--- a/libs/audioflinger/AudioFlinger.h
+++ b/libs/audioflinger/AudioFlinger.h
@@ -905,7 +905,7 @@ private:
 
         enum effect_state {
             IDLE,
-            RESET,
+            RESTART,
             STARTING,
             ACTIVE,
             STOPPING,
@@ -914,6 +914,7 @@ private:
 
         int         id() { return mId; }
         void process();
+        void updateState();
         status_t command(int cmdCode, int cmdSize, void *pCmdData, int *replySize, void *pReplyData);
 
         void reset_l();
@@ -948,6 +949,9 @@ private:
 
     protected:
 
+        // Maximum time allocated to effect engines to complete the turn off sequence
+        static const uint32_t MAX_DISABLE_TIME_MS = 10000;
+
         EffectModule(const EffectModule&);
         EffectModule& operator = (const EffectModule&);
 
@@ -973,6 +977,9 @@ private:
         status_t mStatus;               // initialization status
         uint32_t mState;                // current activation state (effect_state)
         Vector< wp<EffectHandle> > mHandles;    // list of client handles
+        uint32_t mMaxDisableWaitCnt;    // maximum grace period before forcing an effect off after
+                                        // sending disable command.
+        uint32_t mDisableWaitCnt;       // current process() calls count during disable period.
     };
 
     // The EffectHandle class implements the IEffect interface. It provides resources
diff --git a/media/libeffects/EffectEqualizer.cpp b/media/libeffects/EffectEqualizer.cpp
index d19c6b9fdbcb..af0c411aa725 100644
--- a/media/libeffects/EffectEqualizer.cpp
+++ b/media/libeffects/EffectEqualizer.cpp
@@ -30,6 +30,12 @@
 // effect_interface_t interface implementation for equalizer effect
 extern "C" const struct effect_interface_s gEqualizerInterface;
 
+enum equalizer_state_e {
+    EQUALIZER_STATE_UNINITIALIZED,
+    EQUALIZER_STATE_INITIALIZED,
+    EQUALIZER_STATE_ACTIVE,
+};
+
 namespace android {
 namespace {
 
@@ -100,6 +106,7 @@ struct EqualizerContext {
     effect_config_t config;
     FormatAdapter adapter;
     AudioEqualizer * pEqualizer;
+    uint32_t state;
 };
 
 //--- local function prototypes
@@ -151,6 +158,7 @@ extern "C" int EffectCreate(effect_uuid_t *uuid,
 
     pContext->itfe = &gEqualizerInterface;
     pContext->pEqualizer = NULL;
+    pContext->state = EQUALIZER_STATE_UNINITIALIZED;
 
     ret = Equalizer_init(pContext);
     if (ret < 0) {
@@ -160,6 +168,7 @@ extern "C" int EffectCreate(effect_uuid_t *uuid,
     }
 
     *pInterface = (effect_interface_t)pContext;
+    pContext->state = EQUALIZER_STATE_INITIALIZED;
 
     LOGV("EffectLibCreateEffect %p, size %d", pContext, AudioEqualizer::GetInstanceSize(kNumBands)+sizeof(EqualizerContext));
 
@@ -175,6 +184,7 @@ extern "C" int EffectRelease(effect_interface_t interface) {
         return -EINVAL;
     }
 
+    pContext->state = EQUALIZER_STATE_UNINITIALIZED;
     pContext->pEqualizer->free();
     delete pContext;
 
@@ -528,6 +538,13 @@ extern "C" int Equalizer_process(effect_interface_t self, audio_buffer_t *inBuff
         return -EINVAL;
     }
 
+    if (pContext->state == EQUALIZER_STATE_UNINITIALIZED) {
+        return -EINVAL;
+    }
+    if (pContext->state == EQUALIZER_STATE_INITIALIZED) {
+        return -ENODATA;
+    }
+
     pContext->adapter.process(inBuffer->raw, outBuffer->raw, outBuffer->frameCount);
 
     return 0;
@@ -539,7 +556,7 @@ extern "C" int Equalizer_command(effect_interface_t self, int cmdCode, int cmdSi
     android::EqualizerContext * pContext = (android::EqualizerContext *) self;
     int retsize;
 
-    if (pContext == NULL) {
+    if (pContext == NULL || pContext->state == EQUALIZER_STATE_UNINITIALIZED) {
         return -EINVAL;
     }
 
@@ -594,10 +611,25 @@ extern "C" int Equalizer_command(effect_interface_t self, int cmdCode, int cmdSi
                 p->data + p->psize);
         } break;
     case EFFECT_CMD_ENABLE:
+        if (pReplyData == NULL || *replySize != sizeof(int)) {
+            return -EINVAL;
+        }
+        if (pContext->state != EQUALIZER_STATE_INITIALIZED) {
+            return -ENOSYS;
+        }
+        pContext->state = EQUALIZER_STATE_ACTIVE;
+        LOGV("EFFECT_CMD_ENABLE() OK");
+        *(int *)pReplyData = 0;
+        break;
     case EFFECT_CMD_DISABLE:
         if (pReplyData == NULL || *replySize != sizeof(int)) {
             return -EINVAL;
         }
+        if (pContext->state != EQUALIZER_STATE_ACTIVE) {
+            return -ENOSYS;
+        }
+        pContext->state = EQUALIZER_STATE_INITIALIZED;
+        LOGV("EFFECT_CMD_DISABLE() OK");
         *(int *)pReplyData = 0;
         break;
     case EFFECT_CMD_SET_DEVICE:
diff --git a/media/libeffects/EffectReverb.c b/media/libeffects/EffectReverb.c
index 5c87f23c4357..2ce755897fee 100644
--- a/media/libeffects/EffectReverb.c
+++ b/media/libeffects/EffectReverb.c
@@ -15,8 +15,7 @@
  */
 
 #define LOG_TAG "EffectReverb"
-//
-#define LOG_NDEBUG 0
+//#define LOG_NDEBUG 0
 #include <cutils/log.h>
 #include <stdlib.h>
 #include <string.h>
@@ -143,6 +142,8 @@ int EffectCreate(effect_uuid_t *uuid,
 
     module->itfe = &gReverbInterface;
 
+    module->context.mState = REVERB_STATE_UNINITIALIZED;
+
     if (memcmp(&desc->type, SL_IID_PRESETREVERB, sizeof(effect_uuid_t)) == 0) {
         preset = 1;
     }
@@ -158,6 +159,8 @@ int EffectCreate(effect_uuid_t *uuid,
 
     *pInterface = (effect_interface_t) module;
 
+    module->context.mState = REVERB_STATE_INITIALIZED;
+
     LOGV("EffectLibCreateEffect %p ,size %d", module, sizeof(reverb_module_t));
 
     return 0;
@@ -171,6 +174,8 @@ int EffectRelease(effect_interface_t interface) {
         return -EINVAL;
     }
 
+    pRvbModule->context.mState = REVERB_STATE_UNINITIALIZED;
+
     free(pRvbModule);
     return 0;
 }
@@ -195,6 +200,13 @@ static int Reverb_Process(effect_interface_t self, audio_buffer_t *inBuffer, aud
 
     pReverb = (reverb_object_t*) &pRvbModule->context;
 
+    if (pReverb->mState == REVERB_STATE_UNINITIALIZED) {
+        return -EINVAL;
+    }
+    if (pReverb->mState == REVERB_STATE_INITIALIZED) {
+        return -ENODATA;
+    }
+
     //if bypassed or the preset forces the signal to be completely dry
     if (pReverb->m_bBypass != 0) {
         if (inBuffer->raw != outBuffer->raw) {
@@ -257,13 +269,15 @@ static int Reverb_Process(effect_interface_t self, audio_buffer_t *inBuffer, aud
     return 0;
 }
 
+
 static int Reverb_Command(effect_interface_t self, int cmdCode, int cmdSize,
         void *pCmdData, int *replySize, void *pReplyData) {
     reverb_module_t *pRvbModule = (reverb_module_t *) self;
     reverb_object_t *pReverb;
     int retsize;
 
-    if (pRvbModule == NULL) {
+    if (pRvbModule == NULL ||
+            pRvbModule->context.mState == REVERB_STATE_UNINITIALIZED) {
         return -EINVAL;
     }
 
@@ -277,6 +291,9 @@ static int Reverb_Command(effect_interface_t self, int cmdCode, int cmdSize,
             return -EINVAL;
         }
         *(int *) pReplyData = Reverb_Init(pRvbModule, pReverb->m_Aux, pReverb->m_Preset);
+        if (*(int *) pReplyData == 0) {
+            pRvbModule->context.mState = REVERB_STATE_INITIALIZED;
+        }
         break;
     case EFFECT_CMD_CONFIGURE:
         if (pCmdData == NULL || cmdSize != sizeof(effect_config_t)
@@ -315,10 +332,25 @@ static int Reverb_Command(effect_interface_t self, int cmdCode, int cmdSize,
                 cmd->vsize, cmd->data + sizeof(int32_t));
         break;
     case EFFECT_CMD_ENABLE:
+        if (pReplyData == NULL || *replySize != sizeof(int)) {
+            return -EINVAL;
+        }
+        if (pReverb->mState != REVERB_STATE_INITIALIZED) {
+            return -ENOSYS;
+        }
+        pReverb->mState = REVERB_STATE_ACTIVE;
+        LOGV("EFFECT_CMD_ENABLE() OK");
+        *(int *)pReplyData = 0;
+        break;
     case EFFECT_CMD_DISABLE:
         if (pReplyData == NULL || *replySize != sizeof(int)) {
             return -EINVAL;
         }
+        if (pReverb->mState != REVERB_STATE_ACTIVE) {
+            return -ENOSYS;
+        }
+        pReverb->mState = REVERB_STATE_INITIALIZED;
+        LOGV("EFFECT_CMD_DISABLE() OK");
         *(int *)pReplyData = 0;
         break;
     case EFFECT_CMD_SET_DEVICE:
diff --git a/media/libeffects/EffectReverb.h b/media/libeffects/EffectReverb.h
index 5af316d0f0cb..ee8e3905ef0c 100644
--- a/media/libeffects/EffectReverb.h
+++ b/media/libeffects/EffectReverb.h
@@ -114,6 +114,12 @@ int32_t nPanG1 = -1.0 for cos
 #define AP1_GAIN_RANGE (int)(22936-6553)
 
 
+enum reverb_state_e {
+    REVERB_STATE_UNINITIALIZED,
+    REVERB_STATE_INITIALIZED,
+    REVERB_STATE_ACTIVE,
+};
+
 /* parameters for each allpass */
 typedef struct
 {
@@ -279,6 +285,7 @@ typedef struct
     uint16_t            m_Aux;                // if TRUE, is connected as auxiliary effect
     uint16_t            m_Preset;             // if TRUE, expose preset revert interface
 
+    uint32_t            mState;
 } reverb_object_t;
 
 
diff --git a/media/libeffects/EffectVisualizer.cpp b/media/libeffects/EffectVisualizer.cpp
index f27e296cb8c4..bcda06e8ae57 100644
--- a/media/libeffects/EffectVisualizer.cpp
+++ b/media/libeffects/EffectVisualizer.cpp
@@ -231,7 +231,7 @@ extern "C" int Visualizer_process(
         return -EINVAL;
     }
     if (pContext->mState != VISUALIZER_STATE_ACTIVE) {
-        return -ENOSYS;
+        return -ENODATA;
     }
 
     if (inBuffer == NULL || inBuffer->raw == NULL ||