From 70670e63cec845ae61fe34059475c1919a2f078a Mon Sep 17 00:00:00 2001
From: Chavi Weingarten <chaviw@google.com>
Date: Wed, 22 Feb 2023 17:36:40 +0000
Subject: [BBQ] Only update destination frame when buffer matches requested

The current code in BBQ won't reject the buffer if the buffer size and
last size match, even if requested size doesn't match. This is fine as
long as we don't also update the destination frame to the new requested
size. We can apply the old buffer, so we don't drop additional buffers,
but keep the last destination frame as the last requested size. When we
get a new buffer that matches the new requested size, we can update the
destination frame.

Without this fix, the buffer could be stretched in FREEZE mode since the
buffer size will end up not matching the destination frame set in SF.

Test: SurfaceSyncGroupContinuousTest
Fixes: 267284591
Change-Id: Id8bc8b6e04fa1cc56f7b9eb609cadb208b27b3ea
---
 libs/gui/BLASTBufferQueue.cpp | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

(limited to 'libs/gui/BLASTBufferQueue.cpp')

diff --git a/libs/gui/BLASTBufferQueue.cpp b/libs/gui/BLASTBufferQueue.cpp
index 9d82c143f5..cf8b13ffa4 100644
--- a/libs/gui/BLASTBufferQueue.cpp
+++ b/libs/gui/BLASTBufferQueue.cpp
@@ -486,6 +486,17 @@ void BLASTBufferQueue::releaseBuffer(const ReleaseCallbackId& callbackId,
     mSyncedFrameNumbers.erase(callbackId.framenumber);
 }
 
+static ui::Size getBufferSize(const BufferItem& item) {
+    uint32_t bufWidth = item.mGraphicBuffer->getWidth();
+    uint32_t bufHeight = item.mGraphicBuffer->getHeight();
+
+    // Take the buffer's orientation into account
+    if (item.mTransform & ui::Transform::ROT_90) {
+        std::swap(bufWidth, bufHeight);
+    }
+    return ui::Size(bufWidth, bufHeight);
+}
+
 status_t BLASTBufferQueue::acquireNextBufferLocked(
         const std::optional<SurfaceComposerClient::Transaction*> transaction) {
     // Check if we have frames available and we have not acquired the maximum number of buffers.
@@ -563,7 +574,12 @@ status_t BLASTBufferQueue::acquireNextBufferLocked(
     // Ensure BLASTBufferQueue stays alive until we receive the transaction complete callback.
     incStrong((void*)transactionCallbackThunk);
 
-    mSize = mRequestedSize;
+    // Only update mSize for destination bounds if the incoming buffer matches the requested size.
+    // Otherwise, it could cause stretching since the destination bounds will update before the
+    // buffer with the new size is acquired.
+    if (mRequestedSize == getBufferSize(bufferItem)) {
+        mSize = mRequestedSize;
+    }
     Rect crop = computeCrop(bufferItem);
     mLastBufferInfo.update(true /* hasBuffer */, bufferItem.mGraphicBuffer->getWidth(),
                            bufferItem.mGraphicBuffer->getHeight(), bufferItem.mTransform,
@@ -834,14 +850,7 @@ bool BLASTBufferQueue::rejectBuffer(const BufferItem& item) {
         return false;
     }
 
-    uint32_t bufWidth = item.mGraphicBuffer->getWidth();
-    uint32_t bufHeight = item.mGraphicBuffer->getHeight();
-
-    // Take the buffer's orientation into account
-    if (item.mTransform & ui::Transform::ROT_90) {
-        std::swap(bufWidth, bufHeight);
-    }
-    ui::Size bufferSize(bufWidth, bufHeight);
+    ui::Size bufferSize = getBufferSize(item);
     if (mRequestedSize != mSize && mRequestedSize == bufferSize) {
         return false;
     }
-- 
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