commit 8e3e2ea8a946c616140c1df06e395a62c724bacb
author Ady Abraham <adyabr@google.com> Thu Oct 31 15:52:31 2024 -0700
committer Ady Abraham <adyabr@google.com> Fri Nov 01 04:48:18 2024 +0000
tree c6435c1d10367c1171a3fb5fc3474516cce0f804
parent a8217b5de82897fdfb4a427643a1d1c851845e3a

SF: omit vsync callbacks when screen is OFF

This CL is submitted behind a flag and in still in development.
The flag should not be enabled just yet.

Test: manual
Bug: 331636736
Flag: com.android.graphics.surfaceflinger.flags.no_vsyncs_on_screen_off
Change-Id: Iec9cde3bafb9c112c9ce9beebe6dded4727fc99c

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index d35a76a..0ba29f9 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -3660,6 +3660,26 @@
     return display;
 }
 
+void SurfaceFlinger::incRefreshableDisplays() {
+    if (FlagManager::getInstance().no_vsyncs_on_screen_off()) {
+        mRefreshableDisplays++;
+        if (mRefreshableDisplays == 1) {
+            ftl::FakeGuard guard(kMainThreadContext);
+            mScheduler->omitVsyncDispatching(false);
+        }
+    }
+}
+
+void SurfaceFlinger::decRefreshableDisplays() {
+    if (FlagManager::getInstance().no_vsyncs_on_screen_off()) {
+        mRefreshableDisplays--;
+        if (mRefreshableDisplays == 0) {
+            ftl::FakeGuard guard(kMainThreadContext);
+            mScheduler->omitVsyncDispatching(true);
+        }
+    }
+}
+
 void SurfaceFlinger::processDisplayAdded(const wp<IBinder>& displayToken,
                                          const DisplayDeviceState& state) {
     ui::Size resolution(0, 0);
@@ -3751,6 +3771,10 @@
         display->adjustRefreshRate(mScheduler->getPacesetterRefreshRate());
     }
 
+    if (display->isRefreshable()) {
+        incRefreshableDisplays();
+    }
+
     mDisplays.try_emplace(displayToken, std::move(display));
 
     // For an external display, loadDisplayModes already attempted to select the same mode
@@ -3785,6 +3809,10 @@
         } else {
             mScheduler->unregisterDisplay(display->getPhysicalId(), mActiveDisplayId);
         }
+
+        if (display->isRefreshable()) {
+            decRefreshableDisplays();
+        }
     }
 
     mDisplays.erase(displayToken);
@@ -3819,6 +3847,10 @@
             if (display->isVirtual()) {
                 releaseVirtualDisplay(display->getVirtualId());
             }
+
+            if (display->isRefreshable()) {
+                decRefreshableDisplays();
+            }
         }
 
         mDisplays.erase(displayToken);
@@ -5317,7 +5349,15 @@
                      activeDisplay->isPoweredOn(),
              "Trying to change power mode on inactive display without powering off active display");
 
+    const bool couldRefresh = display->isRefreshable();
     display->setPowerMode(mode);
+    const bool canRefresh = display->isRefreshable();
+
+    if (couldRefresh && !canRefresh) {
+        decRefreshableDisplays();
+    } else if (!couldRefresh && canRefresh) {
+        incRefreshableDisplays();
+    }
 
     const auto activeMode = display->refreshRateSelector().getActiveMode().modePtr;
     if (currentMode == hal::PowerMode::OFF) {