commit 7e6c150440c7a21afb92c826d406be411423cd01
author Adithya R <gh0strider.2k18.reborn@gmail.com> Sun Oct 09 20:28:56 2022 +0530
committer SamarV-121 <samar@samarv121.dev> Sun Jun 16 14:01:29 2024 +0530
tree 15c61446bc0567b3b112e7972d4e7322a911118a
parent 226486cdaf606909b5cc9e1f662f0874a6c4d079

SF: Bring back support for disabling backpressure propagation

[Pulkit077]: Adapt to A14 QPR1
[SamarV-121]: Adapt to A14 QPR3

Taken from CLO (QSSI 13). Some Qualcomm devices can still
benefit from disabling backpressure propagation by setting:

debug.sf.disable_backpressure=1

Change-Id: I669a6059a2a971aa79603e74153fa93729f703dc
Signed-off-by: Pulkit077 <pulkitagarwal2k1@gmail.com>

services/surfaceflinger/Scheduler/include/scheduler/Features.h

diff --git a/services/surfaceflinger/Scheduler/include/scheduler/Features.h b/services/surfaceflinger/Scheduler/include/scheduler/Features.h
index 52485fb..6a3d7d0 100644
--- a/services/surfaceflinger/Scheduler/include/scheduler/Features.h
+++ b/services/surfaceflinger/Scheduler/include/scheduler/Features.h
@@ -30,6 +30,7 @@
     kBackpressureGpuComposition = 1 << 4,
     kSmallDirtyContentDetection = 1 << 5,
     kExpectedPresentTime = 1 << 6,
+    kPropagateBackpressure = 1 << 7,
 };
 
 using FeatureFlags = ftl::Flags<Feature>;

services/surfaceflinger/Scheduler/include/scheduler/FrameTargeter.h

diff --git a/services/surfaceflinger/Scheduler/include/scheduler/FrameTargeter.h b/services/surfaceflinger/Scheduler/include/scheduler/FrameTargeter.h
index a5bb6c2..bf1236d 100644
--- a/services/surfaceflinger/Scheduler/include/scheduler/FrameTargeter.h
+++ b/services/surfaceflinger/Scheduler/include/scheduler/FrameTargeter.h
@@ -115,7 +115,8 @@
     FrameTargeter(PhysicalDisplayId displayId, FeatureFlags flags)
           : FrameTarget(to_string(displayId)),
             mBackpressureGpuComposition(flags.test(Feature::kBackpressureGpuComposition)),
-            mSupportsExpectedPresentTime(flags.test(Feature::kExpectedPresentTime)) {}
+            mSupportsExpectedPresentTime(flags.test(Feature::kExpectedPresentTime)),
+            mPropagateBackpressure(flags.test(Feature::kPropagateBackpressure)) {}
 
     const FrameTarget& target() const { return *this; }
 
@@ -151,6 +152,7 @@
 
     const bool mBackpressureGpuComposition;
     const bool mSupportsExpectedPresentTime;
+    const bool mPropagateBackpressure;
 
     TimePoint mScheduledPresentTime;
     CompositionCoverageFlags mCompositionCoverage;

services/surfaceflinger/Scheduler/src/FrameTargeter.cpp

diff --git a/services/surfaceflinger/Scheduler/src/FrameTargeter.cpp b/services/surfaceflinger/Scheduler/src/FrameTargeter.cpp
index 68c277d..ec33c3d 100644
--- a/services/surfaceflinger/Scheduler/src/FrameTargeter.cpp
+++ b/services/surfaceflinger/Scheduler/src/FrameTargeter.cpp
@@ -97,7 +97,7 @@
     //
     // TODO(b/280667110): The grace period should depend on `sfWorkDuration` and `vsyncPeriod` being
     // approximately equal, not whether backpressure propagation is enabled.
-    const int graceTimeForPresentFenceMs = static_cast<int>(
+    const int graceTimeForPresentFenceMs = mPropagateBackpressure && static_cast<int>(
             mBackpressureGpuComposition || !mCompositionCoverage.test(CompositionCoverage::Gpu));
 
     // Pending frames may trigger backpressure propagation.

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index cf5f55d..0fef42e 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -478,6 +478,10 @@
 
     mDebugFlashDelay = base::GetUintProperty("debug.sf.showupdates"s, 0u);
 
+    property_get("debug.sf.disable_backpressure", value, "0");
+    mPropagateBackpressure = !atoi(value);
+    ALOGI_IF(!mPropagateBackpressure, "Disabling backpressure propagation");
+
     mBackpressureGpuComposition = base::GetBoolProperty("debug.sf.enable_gl_backpressure"s, true);
     ALOGI_IF(mBackpressureGpuComposition, "Enabling backpressure for GPU composition");
 
@@ -2548,7 +2552,7 @@
     }
 
     if (pacesetterFrameTarget.isFramePending()) {
-        if (mBackpressureGpuComposition || pacesetterFrameTarget.didMissHwcFrame()) {
+        if (mPropagateBackpressure && (mBackpressureGpuComposition || pacesetterFrameTarget.didMissHwcFrame())) {
             if (FlagManager::getInstance().vrr_config()) {
                 mScheduler->getVsyncSchedule()->getTracker().onFrameMissed(
                         pacesetterFrameTarget.expectedPresentTime());
@@ -4366,6 +4370,9 @@
     if (mBackpressureGpuComposition) {
         features |= Feature::kBackpressureGpuComposition;
     }
+    if (mPropagateBackpressure) {
+        features |= Feature::kPropagateBackpressure;
+    }
     if (getHwComposer().getComposer()->isSupported(
                 Hwc2::Composer::OptionalFeature::ExpectedPresentTime)) {
         features |= Feature::kExpectedPresentTime;

services/surfaceflinger/SurfaceFlinger.h

diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 678be54..d2cf9aa 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -1297,6 +1297,7 @@
     std::atomic_bool mForceFullDamage = false;
 
     bool mLayerCachingEnabled = false;
+    bool mPropagateBackpressure = true;
     bool mBackpressureGpuComposition = false;
 
     LayerTracing mLayerTracing;