Fix override setBufferCount

The logic in setBufferCount was still assuming it needed
to inject the extra buffers, however that injection was
already happening in the min_undequeued query. So it was
increasing buffercount by 2x the extraCount, or concretely
5 buffers when it should have been 4 on >75hz devices

Bug: 168928692
Test: Boot coral, verify 4 buffers instead of 5
Change-Id: I0908228a6791d90544fbf4cb21170931bd31a9db
Merged-In: I0908228a6791d90544fbf4cb21170931bd31a9db

1 files changed, 6 insertions, 3 deletions

diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index a362bd220936..667a7517a24c 100644
--- a/libs/hwui/renderthread/CanvasContext.cpp
+++ b/libs/hwui/renderthread/CanvasContext.cpp
@@ -139,7 +139,7 @@ void CanvasContext::destroy() {
     mAnimationContext->destroy();
 }
 
-static void setBufferCount(ANativeWindow* window, uint32_t extraBuffers) {
+static void setBufferCount(ANativeWindow* window) {
     int query_value;
     int err = window->query(window, NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS, &query_value);
     if (err != 0 || query_value < 0) {
@@ -148,7 +148,9 @@ static void setBufferCount(ANativeWindow* window, uint32_t extraBuffers) {
     }
     auto min_undequeued_buffers = static_cast<uint32_t>(query_value);
 
-    int bufferCount = min_undequeued_buffers + 2 + extraBuffers;
+    // We only need to set min_undequeued + 2 because the renderahead amount was already factored into the
+    // query for min_undequeued
+    int bufferCount = min_undequeued_buffers + 2;
     native_window_set_buffer_count(window, bufferCount);
 }
 
@@ -179,7 +181,8 @@ void CanvasContext::setSurface(ANativeWindow* window, bool enableTimeout) {
             mNativeSurface ? mNativeSurface->getNativeWindow() : nullptr, mSwapBehavior);
 
     if (mNativeSurface && !mNativeSurface->didSetExtraBuffers()) {
-        setBufferCount(mNativeSurface->getNativeWindow(), mRenderAheadCapacity);
+        setBufferCount(mNativeSurface->getNativeWindow());
+
     }
 
     mFrameNumber = -1;