commit 86c80e36c3dc4994a8c24a096cd8f83fec739eb9
author Huihong Luo <huisinro@google.com> Wed Jun 16 15:41:07 2021 -0700
committer Huihong Luo <huisinro@google.com> Mon Jun 28 15:52:12 2021 -0700
tree 396869f0b3288d9903411eec61db57768024fdbf
parent 076276f7b8b5e0501a9f96e564d655020128dc31

Re-introduce debug.sf.latch_unsignaled

This pretty much reverts this commit: Ia453eaf895554adbb2fa9c11c2bc8609e1037ea5.
Some devices may find this helpful to improve performance, but there is a risk of pipeline stall from misbehaving apps.

Bug: 173694115
Test: manual
Merged-In: I48c3095061dc106fa08d36b8ef17eccb04fb6eb1
Change-Id: I48c3095061dc106fa08d36b8ef17eccb04fb6eb1

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index e2f3ebb..7f55cc2 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -310,6 +310,7 @@
 ui::PixelFormat SurfaceFlinger::wideColorGamutCompositionPixelFormat = ui::PixelFormat::RGBA_8888;
 bool SurfaceFlinger::useFrameRateApi;
 bool SurfaceFlinger::enableSdrDimming;
+bool SurfaceFlinger::enableLatchUnsignaled;
 
 std::string decodeDisplayColorSetting(DisplayColorSetting displayColorSetting) {
     switch(displayColorSetting) {
@@ -479,6 +480,8 @@
 
     // Debug property overrides ro. property
     enableSdrDimming = property_get_bool("debug.sf.enable_sdr_dimming", enable_sdr_dimming(false));
+
+    enableLatchUnsignaled = base::GetBoolProperty("debug.sf.latch_unsignaled"s, false);
 }
 
 SurfaceFlinger::~SurfaceFlinger() = default;
@@ -3571,7 +3574,7 @@
     for (const ComposerState& state : states) {
         const layer_state_t& s = state.state;
         const bool acquireFenceChanged = (s.what & layer_state_t::eAcquireFenceChanged);
-        if (acquireFenceChanged && s.acquireFence &&
+        if (acquireFenceChanged && s.acquireFence && !enableLatchUnsignaled &&
             s.acquireFence->getStatus() == Fence::Status::Unsignaled) {
             ATRACE_NAME("fence unsignaled");
             return false;