commit f3441822fb8360cacd2d30bcb6731c2841597fc9
author Huihong Luo <huisinro@google.com> Wed Jun 16 15:41:07 2021 -0700
committer Huihong Luo <huisinro@google.com> Mon Jun 28 21:24:33 2021 +0000
tree 66a638e39d8c5dad43eaf9805fb346fdbfa43539
parent 75fe7e540bf80a76c48b2f73d9a0aafc0b177458

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
Change-Id: I48c3095061dc106fa08d36b8ef17eccb04fb6eb1

services/surfaceflinger/BufferQueueLayer.cpp

diff --git a/services/surfaceflinger/BufferQueueLayer.cpp b/services/surfaceflinger/BufferQueueLayer.cpp
index b236fd2..2fa8936 100644
--- a/services/surfaceflinger/BufferQueueLayer.cpp
+++ b/services/surfaceflinger/BufferQueueLayer.cpp
@@ -126,6 +126,11 @@
 
 bool BufferQueueLayer::fenceHasSignaled() const {
     Mutex::Autolock lock(mQueueItemLock);
+
+    if (SurfaceFlinger::enableLatchUnsignaled) {
+        return true;
+    }
+
     if (!hasFrameUpdate()) {
         return true;
     }

services/surfaceflinger/BufferStateLayer.cpp

diff --git a/services/surfaceflinger/BufferStateLayer.cpp b/services/surfaceflinger/BufferStateLayer.cpp
index 2a49a0a..645e883 100644
--- a/services/surfaceflinger/BufferStateLayer.cpp
+++ b/services/surfaceflinger/BufferStateLayer.cpp
@@ -635,6 +635,10 @@
 // Interface implementation for BufferLayer
 // -----------------------------------------------------------------------
 bool BufferStateLayer::fenceHasSignaled() const {
+    if (SurfaceFlinger::enableLatchUnsignaled) {
+        return true;
+    }
+
     const bool fenceSignaled =
             getDrawingState().acquireFence->getStatus() == Fence::Status::Signaled;
     if (!fenceSignaled) {

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 27f0038..67287a7 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -311,6 +311,7 @@
 ui::PixelFormat SurfaceFlinger::wideColorGamutCompositionPixelFormat = ui::PixelFormat::RGBA_8888;
 bool SurfaceFlinger::useFrameRateApi;
 bool SurfaceFlinger::enableSdrDimming;
+bool SurfaceFlinger::enableLatchUnsignaled;
 
 std::string decodeDisplayColorSetting(DisplayColorSetting displayColorSetting) {
     switch(displayColorSetting) {
@@ -480,6 +481,8 @@
 
     // 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;
@@ -3566,7 +3569,7 @@
     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;

services/surfaceflinger/SurfaceFlinger.h

diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 1d6f016..6cff608 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -270,6 +270,8 @@
     // being treated as native display brightness
     static bool enableSdrDimming;
 
+    static bool enableLatchUnsignaled;
+
     // must be called before clients can connect
     void init() ANDROID_API;