commit ec7aa8a7287629522b4fab712bad465f0d132be4
author Ady Abraham <adyabr@google.com> Mon Jun 28 12:37:09 2021 -0700
committer Ady Abraham <adyabr@google.com> Mon Jun 28 12:38:41 2021 -0700
tree 059c8517ad2df5d50cdb58222606c0674f49b145
parent b3c68852626da31ae79870defbd54bfd9df7ffdf

SF: check previous present fence to avoid early presentation

If SurfaceFlinger finishes composition a vsyncPeriod or more before it
planned to, it sleeps before calling composer to present the frame to
avoid early presentation. In this CL we are removing the sleep if the
previous present fence is still pending, as early presentation is not
possible (composer has already a frame queued).

Bug: 190842189
Test: Bouncy ball while forcing client composition
Change-Id: Id913a21b3489973d82498c6154843656972b6e1a

services/surfaceflinger/CompositionEngine/src/Display.cpp

diff --git a/services/surfaceflinger/CompositionEngine/src/Display.cpp b/services/surfaceflinger/CompositionEngine/src/Display.cpp
index ae1336e..2f2c686 100644
--- a/services/surfaceflinger/CompositionEngine/src/Display.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Display.cpp
@@ -229,7 +229,8 @@
     auto& hwc = getCompositionEngine().getHwComposer();
     if (status_t result =
                 hwc.getDeviceCompositionChanges(*halDisplayId, anyLayersRequireClientComposition(),
-                                                getState().earliestPresentTime, &changes);
+                                                getState().earliestPresentTime,
+                                                getState().previousPresentFence, &changes);
         result != NO_ERROR) {
         ALOGE("chooseCompositionStrategy failed for %s: %d (%s)", getName().c_str(), result,
               strerror(-result));
@@ -330,7 +331,8 @@
     }
 
     auto& hwc = getCompositionEngine().getHwComposer();
-    hwc.presentAndGetReleaseFences(*halDisplayIdOpt, getState().earliestPresentTime);
+    hwc.presentAndGetReleaseFences(*halDisplayIdOpt, getState().earliestPresentTime,
+                                   getState().previousPresentFence);
 
     fences.presentFence = hwc.getPresentFence(*halDisplayIdOpt);