1 files changed, 29 insertions, 2 deletions

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 1237ee4320..4e73bfa6b7 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1781,6 +1781,7 @@ void SurfaceFlinger::rebuildLayerStacks() {
             Region opaqueRegion;
             Region dirtyRegion;
             Vector<sp<Layer>> layersSortedByZ;
+            Vector<sp<Layer>> layersNeedingFences;
             const sp<DisplayDevice>& displayDevice(mDisplays[dpy]);
             const Transform& tr(displayDevice->getTransform());
             const Rect bounds(displayDevice->getBounds());
@@ -1788,6 +1789,7 @@ void SurfaceFlinger::rebuildLayerStacks() {
                 computeVisibleRegions(displayDevice, dirtyRegion, opaqueRegion);
 
                 mDrawingState.traverseInZOrder([&](Layer* layer) {
+                    bool hwcLayerDestroyed = false;
                     if (layer->belongsToDisplay(displayDevice->getLayerStack(),
                                 displayDevice->isPrimary())) {
                         Region drawRegion(tr.transform(
@@ -1798,18 +1800,32 @@ void SurfaceFlinger::rebuildLayerStacks() {
                         } else {
                             // Clear out the HWC layer if this layer was
                             // previously visible, but no longer is
-                            layer->destroyHwcLayer(
+                            hwcLayerDestroyed = layer->destroyHwcLayer(
                                     displayDevice->getHwcDisplayId());
                         }
                     } else {
                         // WM changes displayDevice->layerStack upon sleep/awake.
                         // Here we make sure we delete the HWC layers even if
                         // WM changed their layer stack.
-                        layer->destroyHwcLayer(displayDevice->getHwcDisplayId());
+                        hwcLayerDestroyed = layer->destroyHwcLayer(
+                                displayDevice->getHwcDisplayId());
+                    }
+
+                    // If a layer is not going to get a release fence because
+                    // it is invisible, but it is also going to release its
+                    // old buffer, add it to the list of layers needing
+                    // fences.
+                    if (hwcLayerDestroyed) {
+                        auto found = std::find(mLayersWithQueuedFrames.cbegin(),
+                                mLayersWithQueuedFrames.cend(), layer);
+                        if (found != mLayersWithQueuedFrames.cend()) {
+                            layersNeedingFences.add(layer);
+                        }
                     }
                 });
             }
             displayDevice->setVisibleLayersSortedByZ(layersSortedByZ);
+            displayDevice->setLayersNeedingFences(layersNeedingFences);
             displayDevice->undefinedRegion.set(bounds);
             displayDevice->undefinedRegion.subtractSelf(
                     tr.transform(opaqueRegion));
@@ -2046,6 +2062,17 @@ void SurfaceFlinger::postFramebuffer()
             }
             layer->onLayerDisplayed(releaseFence);
         }
+
+        // We've got a list of layers needing fences, that are disjoint with
+        // displayDevice->getVisibleLayersSortedByZ.  The best we can do is to
+        // supply them with the present fence.
+        if (!displayDevice->getLayersNeedingFences().isEmpty()) {
+            sp<Fence> presentFence = mHwc->getPresentFence(hwcId);
+            for (auto& layer : displayDevice->getLayersNeedingFences()) {
+                layer->onLayerDisplayed(presentFence);
+            }
+        }
+
         if (hwcId >= 0) {
             mHwc->clearReleaseFences(hwcId);
         }