Remove legacy disable triple buffering config

The config changes the dequeue limit of BQ (setMaxDequeuedBufferCount) from 2 to 1,  decreasing the default size of the queue from (3 to 2).
Some of the motivations behind this change include:
- not applicable in most scenarios since producers in the system override this
- breaks async mode, not well tested in other scenarios
- simplifying some of the implementation and removes a configuration/flag.

Clients can still manually call setMaxDequeuedBufferCount if they wish.

Test: presubmit
Fixes: 182314340
Change-Id: Iea88e8a795b91ff325610cfb1eefbcfe6e434841

5 files changed, 5 insertions, 24 deletions

diff --git a/libs/gui/BLASTBufferQueue.cpp b/libs/gui/BLASTBufferQueue.cpp
index 82c9268feb..9490314b71 100644
--- a/libs/gui/BLASTBufferQueue.cpp
+++ b/libs/gui/BLASTBufferQueue.cpp
@@ -130,8 +130,7 @@ void BLASTBufferItemConsumer::onSidebandStreamChanged() {
 }
 
 BLASTBufferQueue::BLASTBufferQueue(const std::string& name, const sp<SurfaceControl>& surface,
-                                   int width, int height, int32_t format,
-                                   bool enableTripleBuffering)
+                                   int width, int height, int32_t format)
       : mName(name),
         mSurfaceControl(surface),
         mSize(width, height),
@@ -143,9 +142,8 @@ BLASTBufferQueue::BLASTBufferQueue(const std::string& name, const sp<SurfaceCont
     // explicitly so that dequeueBuffer will block
     mProducer->setDequeueTimeout(std::numeric_limits<int64_t>::max());
 
-    if (enableTripleBuffering) {
-        mProducer->setMaxDequeuedBufferCount(2);
-    }
+    // safe default, most producers are expected to override this
+    mProducer->setMaxDequeuedBufferCount(2);
     mBufferItemConsumer = new BLASTBufferItemConsumer(mConsumer,
                                                       GraphicBuffer::USAGE_HW_COMPOSER |
                                                               GraphicBuffer::USAGE_HW_TEXTURE,
diff --git a/libs/gui/include/gui/BLASTBufferQueue.h b/libs/gui/include/gui/BLASTBufferQueue.h
index dd8e714e23..9516bfb4b0 100644
--- a/libs/gui/include/gui/BLASTBufferQueue.h
+++ b/libs/gui/include/gui/BLASTBufferQueue.h
@@ -74,7 +74,7 @@ class BLASTBufferQueue
 {
 public:
     BLASTBufferQueue(const std::string& name, const sp<SurfaceControl>& surface, int width,
-                     int height, int32_t format, bool enableTripleBuffering = true);
+                     int height, int32_t format);
 
     sp<IGraphicBufferProducer> getIGraphicBufferProducer() const {
         return mProducer;
diff --git a/services/surfaceflinger/BufferQueueLayer.cpp b/services/surfaceflinger/BufferQueueLayer.cpp
index 63dd25f72f..c0ce84f31b 100644
--- a/services/surfaceflinger/BufferQueueLayer.cpp
+++ b/services/surfaceflinger/BufferQueueLayer.cpp
@@ -521,10 +521,7 @@ void BufferQueueLayer::onFirstRef() {
     mConsumer->setContentsChangedListener(mContentsChangedListener);
     mConsumer->setName(String8(mName.data(), mName.size()));
 
-    // BufferQueueCore::mMaxDequeuedBufferCount is default to 1
-    if (!mFlinger->isLayerTripleBufferingDisabled()) {
-        mProducer->setMaxDequeuedBufferCount(2);
-    }
+    mProducer->setMaxDequeuedBufferCount(2);
 }
 
 status_t BufferQueueLayer::setDefaultBufferProperties(uint32_t w, uint32_t h, PixelFormat format) {
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 9da94832ae..284c715ef9 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -441,10 +441,6 @@ SurfaceFlinger::SurfaceFlinger(Factory& factory) : SurfaceFlinger(factory, SkipI
     mUseHwcVirtualDisplays = atoi(value);
     ALOGI_IF(mUseHwcVirtualDisplays, "Enabling HWC virtual displays");
 
-    property_get("ro.sf.disable_triple_buffer", value, "0");
-    mLayerTripleBufferingDisabled = atoi(value);
-    ALOGI_IF(mLayerTripleBufferingDisabled, "Disabling Triple Buffering");
-
     property_get("ro.surface_flinger.supports_background_blur", value, "0");
     bool supportsBlurs = atoi(value);
     mSupportsBlur = supportsBlurs;
@@ -4549,9 +4545,6 @@ void SurfaceFlinger::logFrameStats() {
 void SurfaceFlinger::appendSfConfigString(std::string& result) const {
     result.append(" [sf");
 
-    if (isLayerTripleBufferingDisabled())
-        result.append(" DISABLE_TRIPLE_BUFFERING");
-
     StringAppendF(&result, " PRESENT_TIME_OFFSET=%" PRId64, dispSyncPresentTimeOffset);
     StringAppendF(&result, " FORCE_HWC_FOR_RBG_TO_YUV=%d", useHwcForRgbToYuv);
     StringAppendF(&result, " MAX_VIRT_DISPLAY_DIM=%" PRIu64, maxVirtualDisplaySize);
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 3787b9db89..779859a7ad 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -1093,10 +1093,6 @@ private:
     void dumpOffscreenLayers(std::string& result) EXCLUDES(mStateLock);
     void dumpPlannerInfo(const DumpArgs& args, std::string& result) const REQUIRES(mStateLock);
 
-    bool isLayerTripleBufferingDisabled() const {
-        return this->mLayerTripleBufferingDisabled;
-    }
-
     status_t doDump(int fd, const DumpArgs& args, bool asProto);
 
     status_t dumpCritical(int fd, const DumpArgs&, bool asProto);
@@ -1250,9 +1246,6 @@ private:
 
     TransactionCallbackInvoker mTransactionCallbackInvoker;
 
-    // Restrict layers to use two buffers in their bufferqueues.
-    bool mLayerTripleBufferingDisabled = false;
-
     // these are thread safe
     std::unique_ptr<MessageQueue> mEventQueue;
     FrameTracker mAnimFrameTracker;