audioflinger: implement Bluetooth latency mode control

Generalize latency mode control previously
only implemented on spatializer thread to mixer threads.
For mixer threads, latency mode control is used when a
Bluetooth A2DP or LE audio device is selected and the
audio HAL stream supports sevreal latency modes.

The following methods and class members are moved from
SpatializerThread class to MixerThread class:
  - onHalLatencyModesChanged_l()
  - getSupportedLatencyModes()
  - mSetLatencyMode
  - mSupportedLatencyModes

setHalLatencyMode_l() has a different implementation in
SpatializerThread and MixerThread.

Test: make
Bug: 257922898
Change-Id: I25106fcb7c3dd9fdeabfbbe29941c7cd3be22196
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 1f0f13a..4ab4557 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -376,8 +376,6 @@
     virtual     void        toAudioPortConfig(struct audio_port_config *config) = 0;
 
     virtual     void        resizeInputBuffer_l(int32_t maxSharedAudioHistoryMs);
-    virtual     void        onHalLatencyModesChanged_l() {}
-
 
                 // see note at declaration of mStandby, mOutDevice and mInDevice
                 bool        standby() const { return mStandby; }
@@ -625,6 +623,8 @@
 
                 product_strategy_t getStrategyForStream(audio_stream_type_t stream) const;
 
+    virtual     void        onHalLatencyModesChanged_l() {}
+
     virtual     void        dumpInternals_l(int fd __unused, const Vector<String16>& args __unused)
                             { }
     virtual     void        dumpTracks_l(int fd __unused, const Vector<String16>& args __unused) { }
@@ -1102,7 +1102,9 @@
                     return INVALID_OPERATION;
                 }
 
-    virtual     status_t setBluetoothVariableLatencyEnabled(bool enabled);
+    virtual     status_t setBluetoothVariableLatencyEnabled(bool enabled __unused) {
+                    return INVALID_OPERATION;
+                }
 
                 void startMelComputation(const sp<audio_utils::MelProcessor>& processor);
                 void stopMelComputation();
@@ -1462,12 +1464,10 @@
     virtual     void flushHw_l() {
                     mIsTimestampAdvancing.clear();
                 }
-
-        // Bluetooth Variable latency control logic is enabled or disabled for this thread
-        std::atomic_bool mBluetoothLatencyModesEnabled;
 };
 
-class MixerThread : public PlaybackThread {
+class MixerThread : public PlaybackThread,
+                    public StreamOutHalInterfaceLatencyModeCallback  {
 public:
     MixerThread(const sp<AudioFlinger>& audioFlinger,
                 AudioStreamOut* output,
@@ -1477,6 +1477,13 @@
                 audio_config_base_t *mixerConfig = nullptr);
     virtual             ~MixerThread();
 
+    // RefBase
+    virtual     void        onFirstRef();
+
+                // StreamOutHalInterfaceLatencyModeCallback
+                void        onRecommendedLatencyModeChanged(
+                                    std::vector<audio_latency_mode_t> modes) override;
+
     // Thread virtuals
 
     virtual     bool        checkForNewParameter_l(const String8& keyValuePair,
@@ -1513,6 +1520,17 @@
     virtual     status_t    releaseAudioPatch_l(const audio_patch_handle_t handle);
 
                 AudioMixer* mAudioMixer;    // normal mixer
+
+            // Support low latency mode by default as unless explicitly indicated by the audio HAL
+            // we assume the audio path is compatible with the head tracking latency requirements
+            std::vector<audio_latency_mode_t> mSupportedLatencyModes = {AUDIO_LATENCY_MODE_LOW};
+            // default to invalid value to force first update to the audio HAL
+            audio_latency_mode_t mSetLatencyMode =
+                    (audio_latency_mode_t)AUDIO_LATENCY_MODE_INVALID;
+
+            // Bluetooth Variable latency control logic is enabled or disabled for this thread
+            std::atomic_bool mBluetoothLatencyModesEnabled;
+
 private:
                 // one-time initialization, no locks required
                 sp<FastMixer>     mFastMixer;     // non-0 if there is also a fast mixer
@@ -1546,6 +1564,11 @@
                                 return INVALID_OPERATION;
                             }
 
+                status_t    getSupportedLatencyModes(
+                                    std::vector<audio_latency_mode_t>* modes) override;
+
+                status_t    setBluetoothVariableLatencyEnabled(bool enabled) override;
+
 protected:
     virtual     void       setMasterMono_l(bool mono) {
                                mMasterMono.store(mono);
@@ -1564,6 +1587,10 @@
                                    mFastMixer->setMasterBalance(balance);
                                }
                            }
+
+                void       updateHalSupportedLatencyModes_l();
+                void       onHalLatencyModesChanged_l() override;
+                void       setHalLatencyMode_l() override;
 };
 
 class DirectOutputThread : public PlaybackThread {
@@ -1767,8 +1794,7 @@
     }
 };
 
-class SpatializerThread : public MixerThread,
-        public StreamOutHalInterfaceLatencyModeCallback {
+class SpatializerThread : public MixerThread {
 public:
     SpatializerThread(const sp<AudioFlinger>& audioFlinger,
                            AudioStreamOut* output,
@@ -1779,32 +1805,16 @@
 
             bool hasFastMixer() const override { return false; }
 
-            status_t    createAudioPatch_l(const struct audio_patch *patch,
-                                   audio_patch_handle_t *handle) override;
-
             // RefBase
             virtual void        onFirstRef();
 
-            // StreamOutHalInterfaceLatencyModeCallback
-            void onRecommendedLatencyModeChanged(std::vector<audio_latency_mode_t> modes) override;
-
             status_t setRequestedLatencyMode(audio_latency_mode_t mode) override;
-            status_t getSupportedLatencyModes(std::vector<audio_latency_mode_t>* modes) override;
 
 protected:
             void checkOutputStageEffects() override;
-            void onHalLatencyModesChanged_l() override;
             void setHalLatencyMode_l() override;
 
 private:
-            void updateHalSupportedLatencyModes_l();
-
-            // Support low latency mode by default as unless explicitly indicated by the audio HAL
-            // we assume the audio path is compatible with the head tracking latency requirements
-            std::vector<audio_latency_mode_t> mSupportedLatencyModes = {AUDIO_LATENCY_MODE_LOW};
-            // default to invalid value to force first update to the audio HAL
-            audio_latency_mode_t mSetLatencyMode =
-                    (audio_latency_mode_t)AUDIO_LATENCY_MODE_INVALID;
             // Do not request a specific mode by default
             audio_latency_mode_t mRequestedLatencyMode = AUDIO_LATENCY_MODE_FREE;