commit 1768cb03cf1ea51ec18f2514f8afa086b6314ba5
author Huihong Luo <huisinro@google.com> Tue Oct 11 11:10:34 2022 -0700
committer Huihong Luo <huisinro@google.com> Mon Jan 30 12:43:40 2023 -0800
tree 05589b03c3d389989fb2884c4393842a366a3526
parent 67011ef83d09d93fa8237cbd33be3960f3152a68

Variable refresh rate for virtual display

Allow virtual display to request a refresh rate, so it can be different
from VSYNC frequencies. SurfaceFlinger drops frames for the
corresponding virtual display based on the refresh rate.

Bug: 241286579
Test: atest libgui_test libsurfaceflinger_unittest SurfaceFlinger_test
Change-Id: I4fba0e553618bb4c7333514b16206ae4277acf72

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 7d0dc93..fe4ae02 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -512,7 +512,8 @@
     mScheduler->run();
 }
 
-sp<IBinder> SurfaceFlinger::createDisplay(const String8& displayName, bool secure) {
+sp<IBinder> SurfaceFlinger::createDisplay(const String8& displayName, bool secure,
+                                          float requestedRefreshRate) {
     // onTransact already checks for some permissions, but adding an additional check here.
     // This is to ensure that only system and graphics can request to create a secure
     // display. Secure displays can show secure content so we add an additional restriction on it.
@@ -543,6 +544,7 @@
     DisplayDeviceState state;
     state.isSecure = secure;
     state.displayName = displayName;
+    state.requestedRefreshRate = Fps::fromValue(requestedRefreshRate);
     mCurrentState.displays.add(token, state);
     return token;
 }
@@ -2343,7 +2345,15 @@
     refreshArgs.outputs.reserve(displays.size());
     std::vector<DisplayId> displayIds;
     for (const auto& [_, display] : displays) {
-        refreshArgs.outputs.push_back(display->getCompositionDisplay());
+        bool dropFrame = false;
+        if (display->isVirtual()) {
+            Fps refreshRate = display->getAdjustedRefreshRate();
+            using fps_approx_ops::operator>;
+            dropFrame = (refreshRate > 0_Hz) && !mScheduler->isVsyncInPhase(frameTime, refreshRate);
+        }
+        if (!dropFrame) {
+            refreshArgs.outputs.push_back(display->getCompositionDisplay());
+        }
         displayIds.push_back(display->getId());
     }
     mPowerAdvisor->setDisplays(displayIds);
@@ -3082,6 +3092,8 @@
     creationArgs.initialPowerMode =
             state.isVirtual() ? std::make_optional(hal::PowerMode::ON) : std::nullopt;
 
+    creationArgs.requestedRefreshRate = state.requestedRefreshRate;
+
     sp<DisplayDevice> display = getFactory().createDisplayDevice(creationArgs);
 
     nativeWindowSurface->preallocateBuffers();
@@ -3198,6 +3210,10 @@
         dispatchDisplayHotplugEvent(displayId, true);
     }
 
+    if (display->isVirtual()) {
+        display->adjustRefreshRate(mScheduler->getLeaderRefreshRate());
+    }
+
     mDisplays.try_emplace(displayToken, std::move(display));
 }
 
@@ -7448,13 +7464,14 @@
 }
 
 binder::Status SurfaceComposerAIDL::createDisplay(const std::string& displayName, bool secure,
+                                                  float requestedRefreshRate,
                                                   sp<IBinder>* outDisplay) {
     status_t status = checkAccessPermission();
     if (status != OK) {
         return binderStatusFromStatusT(status);
     }
     String8 displayName8 = String8::format("%s", displayName.c_str());
-    *outDisplay = mFlinger->createDisplay(displayName8, secure);
+    *outDisplay = mFlinger->createDisplay(displayName8, secure, requestedRefreshRate);
     return binder::Status::ok();
 }