From 1506b181085e1f2156283d0e7b62fe94a918427f Mon Sep 17 00:00:00 2001
From: Vishnu Nair <vishnun@google.com>
Date: Mon, 22 Feb 2021 14:35:15 -0800
Subject: Introduce release buffer callback for BufferStateLayer

Currently BLAST clients use the TransactionCompleted callbacks to
determine when to release buffers. The TransactionCompleted callback
is overloaded. For transactions without buffers, the callback is
called when the transaction is applied on the server. If the
Transaction contains one or more buffers, the callback is called when
all the buffers are latched and ready to be presented. If we have
multiple buffers on multiple transactions, where one or more buffers
maybe dropped, the pending callbacks are called together. This may
delay signaling the client when a buffer can be released.

To fix this, we introduce a new buffer release callback that is
called as soon as a buffer is dropped by the server or when a new
buffer has been latched and the buffer will no longer be presented.
This new callback provides a graphic bufferid to identify the buffer
that can be released and a release fence to wait on.

BlastBufferQueue has been switched to use this new callback. Other
BLAST users continue to use the existing callback.

Test: go/wm-smoke
Test: atest ReleaseBufferCallbackTest
Bug: 178385281

Change-Id: Idd88e4994e543443198a5a8cfa0e3f5f67d5d482
---
 libs/gui/LayerState.cpp | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

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

diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index 6bb8bf2d5b..7a18ca61fe 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -63,7 +63,8 @@ layer_state_t::layer_state_t()
         fixedTransformHint(ui::Transform::ROT_INVALID),
         frameNumber(0),
         frameTimelineInfo(),
-        autoRefresh(false) {
+        autoRefresh(false),
+        releaseBufferListener(nullptr) {
     matrix.dsdx = matrix.dtdy = 1.0f;
     matrix.dsdy = matrix.dtdx = 0.0f;
     hdrMetadata.validTypes = 0;
@@ -152,6 +153,7 @@ status_t layer_state_t::write(Parcel& output) const
     SAFE_PARCEL(output.writeUint64, frameNumber);
     SAFE_PARCEL(frameTimelineInfo.write, output);
     SAFE_PARCEL(output.writeBool, autoRefresh);
+    SAFE_PARCEL(output.writeStrongBinder, IInterface::asBinder(releaseBufferListener));
 
     SAFE_PARCEL(output.writeUint32, blurRegions.size());
     for (auto region : blurRegions) {
@@ -275,6 +277,12 @@ status_t layer_state_t::read(const Parcel& input)
     SAFE_PARCEL(frameTimelineInfo.read, input);
     SAFE_PARCEL(input.readBool, &autoRefresh);
 
+    tmpBinder = nullptr;
+    SAFE_PARCEL(input.readNullableStrongBinder, &tmpBinder);
+    if (tmpBinder) {
+        releaseBufferListener = checked_interface_cast<ITransactionCompletedListener>(tmpBinder);
+    }
+
     uint32_t numRegions = 0;
     SAFE_PARCEL(input.readUint32, &numRegions);
     blurRegions.clear();
@@ -543,6 +551,13 @@ void layer_state_t::merge(const layer_state_t& other) {
         what |= eAutoRefreshChanged;
         autoRefresh = other.autoRefresh;
     }
+    if (other.what & eReleaseBufferListenerChanged) {
+        if (releaseBufferListener) {
+            ALOGW("Overriding releaseBufferListener");
+        }
+        what |= eReleaseBufferListenerChanged;
+        releaseBufferListener = other.releaseBufferListener;
+    }
     if (other.what & eStretchChanged) {
         what |= eStretchChanged;
         stretchEffect = other.stretchEffect;
-- 
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