Remove obsolete debug option

This is dead code, stop maintaining it

Fixes: 159912967
Test: builds
Change-Id: Ia453eaf895554adbb2fa9c11c2bc8609e1037ea5
diff --git a/services/surfaceflinger/BufferLayer.cpp b/services/surfaceflinger/BufferLayer.cpp
index f0b0200..cf60b71 100644
--- a/services/surfaceflinger/BufferLayer.cpp
+++ b/services/surfaceflinger/BufferLayer.cpp
@@ -539,20 +539,6 @@
     return (buffer != 0) && (buffer->getUsage() & GRALLOC_USAGE_PROTECTED);
 }
 
-bool BufferLayer::latchUnsignaledBuffers() {
-    static bool propertyLoaded = false;
-    static bool latch = false;
-    static std::mutex mutex;
-    std::lock_guard<std::mutex> lock(mutex);
-    if (!propertyLoaded) {
-        char value[PROPERTY_VALUE_MAX] = {};
-        property_get("debug.sf.latch_unsignaled", value, "0");
-        latch = atoi(value);
-        propertyLoaded = true;
-    }
-    return latch;
-}
-
 // h/w composer set-up
 bool BufferLayer::allTransactionsSignaled(nsecs_t expectedPresentTime) {
     const auto headFrameNumber = getHeadFrameNumber(expectedPresentTime);
diff --git a/services/surfaceflinger/BufferLayer.h b/services/surfaceflinger/BufferLayer.h
index 26bfb49..2483abb 100644
--- a/services/surfaceflinger/BufferLayer.h
+++ b/services/surfaceflinger/BufferLayer.h
@@ -187,9 +187,6 @@
     bool onPreComposition(nsecs_t) override;
     void preparePerFrameCompositionState() override;
 
-    // Loads the corresponding system property once per process
-    static bool latchUnsignaledBuffers();
-
     // Check all of the local sync points to ensure that all transactions
     // which need to have been applied prior to the frame which is about to
     // be latched have signaled
diff --git a/services/surfaceflinger/BufferQueueLayer.cpp b/services/surfaceflinger/BufferQueueLayer.cpp
index 5f95182..1156f55 100644
--- a/services/surfaceflinger/BufferQueueLayer.cpp
+++ b/services/surfaceflinger/BufferQueueLayer.cpp
@@ -131,10 +131,6 @@
 // -----------------------------------------------------------------------
 
 bool BufferQueueLayer::fenceHasSignaled() const {
-    if (latchUnsignaledBuffers()) {
-        return true;
-    }
-
     if (!hasFrameUpdate()) {
         return true;
     }
diff --git a/services/surfaceflinger/BufferStateLayer.cpp b/services/surfaceflinger/BufferStateLayer.cpp
index 790f2ec..884cc0c 100644
--- a/services/surfaceflinger/BufferStateLayer.cpp
+++ b/services/surfaceflinger/BufferStateLayer.cpp
@@ -422,10 +422,6 @@
 // Interface implementation for BufferLayer
 // -----------------------------------------------------------------------
 bool BufferStateLayer::fenceHasSignaled() const {
-    if (latchUnsignaledBuffers()) {
-        return true;
-    }
-
     const bool fenceSignaled =
             getDrawingState().acquireFence->getStatus() == Fence::Status::Signaled;
     if (!fenceSignaled) {
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index db6f1ad..edafaa5 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -398,10 +398,6 @@
     int debugDdms = atoi(value);
     ALOGI_IF(debugDdms, "DDMS debugging not supported");
 
-    property_get("debug.sf.disable_backpressure", value, "0");
-    mPropagateBackpressure = !atoi(value);
-    ALOGI_IF(!mPropagateBackpressure, "Disabling backpressure propagation");
-
     property_get("debug.sf.enable_gl_backpressure", value, "0");
     mPropagateBackpressureClientComposition = atoi(value);
     ALOGI_IF(mPropagateBackpressureClientComposition,
@@ -1841,10 +1837,7 @@
     // for the present fence to fire instead of just giving up on this frame to handle cases
     // where present fence is just about to get signaled.
     const int graceTimeForPresentFenceMs =
-            (mPropagateBackpressure &&
-             (mPropagateBackpressureClientComposition || !mHadClientComposition))
-            ? 1
-            : 0;
+            (mPropagateBackpressureClientComposition || !mHadClientComposition) ? 1 : 0;
 
     // Pending frames may trigger backpressure propagation.
     const TracedOrdinal<bool> framePending = {"PrevFramePending",
@@ -1903,7 +1896,7 @@
         ON_MAIN_THREAD(setActiveConfigInternal());
     }
 
-    if (framePending && mPropagateBackpressure) {
+    if (framePending) {
         if ((hwcFrameMissed && !gpuFrameMissed) || mPropagateBackpressureClientComposition) {
             signalLayerUpdate();
             return;
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index e9a2905..d8ea501 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -1083,7 +1083,6 @@
     bool mDebugDisableTransformHint = false;
     volatile nsecs_t mDebugInTransaction = 0;
     bool mForceFullDamage = false;
-    bool mPropagateBackpressure = true;
     bool mPropagateBackpressureClientComposition = false;
     std::unique_ptr<SurfaceInterceptor> mInterceptor;