From 0560e0e8ea151004138e6fc39f35fa8985814770 Mon Sep 17 00:00:00 2001
From: Baldev Sahu <bsahu@codeaurora.org>
Date: Thu, 27 Sep 2018 15:02:33 +0530
Subject: [PATCH] sf: Fix issue with dequeueBuffer when multiple display
 present

swapBuffers is called even for device composition when a flip client
target request is present. dequeueBuffer call is skipped
as there is no client composition. This is fine for single display
but if multiple display i.e. vds is present, this will be an issue
as current surface will not be switched and swapBuffers will fail

When flip client target request is present, make sure buffer is
dequeued before swapBuffers.

Bug: 151698217
Test: atest libsurfaceflinger_unittest
Change-Id: I933cbae2f09f81eef6555b1bb1e5991d2c450930
Merged-In: Ia8a1470affb2596b27986cc4153417f48cf4ed1c
---
 services/surfaceflinger/DisplayHardware/HWC2.cpp |  2 +-
 services/surfaceflinger/SurfaceFlinger.cpp       | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/services/surfaceflinger/DisplayHardware/HWC2.cpp b/services/surfaceflinger/DisplayHardware/HWC2.cpp
index c463c4e40a..f4fc7477a3 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2.cpp
@@ -470,7 +470,7 @@ Error Display::getName(std::string* outName) const
 
 Error Display::getRequests(HWC2::DisplayRequest* outDisplayRequests,
                            std::unordered_map<HWC2::Layer*, LayerRequest>* outLayerRequests) {
-    uint32_t intDisplayRequests;
+    uint32_t intDisplayRequests = 0;
     std::vector<Hwc2::Layer> layerIds;
     std::vector<uint32_t> layerRequests;
     auto intError = mComposer.getDisplayRequests(
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index e311e3fae6..30b380183d 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -3415,6 +3415,7 @@ bool SurfaceFlinger::doComposeSurfaces(const sp<DisplayDevice>& displayDevice,
     const Region bounds(displayState.bounds);
     const DisplayRenderArea renderArea(displayDevice);
     const bool hasClientComposition = getHwComposer().hasClientComposition(displayId);
+    const bool hasFlipClientTargetRequest = getHwComposer().hasFlipClientTargetRequest(displayId);
     ATRACE_INT("hasClientComposition", hasClientComposition);
 
     bool applyColorMatrix = false;
@@ -3480,6 +3481,15 @@ bool SurfaceFlinger::doComposeSurfaces(const sp<DisplayDevice>& displayDevice,
         if (applyColorMatrix) {
             clientCompositionDisplay.colorTransform = displayState.colorTransformMat;
         }
+    } else if (hasFlipClientTargetRequest) {
+        buf = display->getRenderSurface()->dequeueBuffer(&fd);
+
+        if (buf == nullptr) {
+            ALOGW("Dequeuing buffer for display [%s] failed, bailing out of "
+                  "client composition for this frame",
+                  displayDevice->getDisplayName().c_str());
+            return false;
+        }
     }
 
     /*