[MD] Single refresh rate selection

Selects the single refresh rate for all the
displays.

BUG: 240743471

Test: atest libsurfaceflinger_unittest
Change-Id: Ifa1bf23bc991fe60e67dba1cb31077e42fd5396e
diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 6d68bac..7f04a4d 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -57,6 +57,39 @@
         }                                                            \
     } while (false)
 
+namespace {
+
+using android::Fps;
+using android::FpsApproxEqual;
+using android::FpsHash;
+using android::scheduler::AggregatedFpsScore;
+using android::scheduler::RefreshRateRankingsAndSignals;
+
+// Returns the aggregated score per Fps for the RefreshRateRankingsAndSignals sourced.
+auto getAggregatedScoresPerFps(
+        const std::vector<RefreshRateRankingsAndSignals>& refreshRateRankingsAndSignalsPerDisplay)
+        -> std::unordered_map<Fps, AggregatedFpsScore, FpsHash, FpsApproxEqual> {
+    std::unordered_map<Fps, AggregatedFpsScore, FpsHash, FpsApproxEqual> aggregatedScoresPerFps;
+
+    for (const auto& refreshRateRankingsAndSignal : refreshRateRankingsAndSignalsPerDisplay) {
+        const auto& refreshRateRankings = refreshRateRankingsAndSignal.refreshRateRankings;
+
+        std::for_each(refreshRateRankings.begin(), refreshRateRankings.end(), [&](const auto& it) {
+            const auto [score, result] =
+                    aggregatedScoresPerFps.try_emplace(it.displayModePtr->getFps(),
+                                                       AggregatedFpsScore{it.score,
+                                                                          /* numDisplays */ 1});
+            if (!result) { // update
+                score->second.totalScore += it.score;
+                score->second.numDisplays++;
+            }
+        });
+    }
+    return aggregatedScoresPerFps;
+}
+
+} // namespace
+
 namespace android::scheduler {
 
 Scheduler::Scheduler(ICompositor& compositor, ISchedulerCallback& callback, FeatureFlags features)
@@ -662,6 +695,7 @@
 auto Scheduler::applyPolicy(S Policy::*statePtr, T&& newState) -> GlobalSignals {
     DisplayModePtr newMode;
     GlobalSignals consideredSignals;
+    std::vector<DisplayModeConfig> displayModeConfigs;
 
     bool refreshRateChanged = false;
     bool frameRateOverridesChanged;
@@ -674,9 +708,27 @@
         if (currentState == newState) return {};
         currentState = std::forward<T>(newState);
 
-        const auto [rankings, signals] = getRankedDisplayModes();
-        newMode = rankings.front().displayModePtr;
-        consideredSignals = signals;
+        displayModeConfigs = getBestDisplayModeConfigs();
+
+        // mPolicy holds the current mode, using the current mode we find out
+        // what display is currently being tracked through the policy and
+        // then find the DisplayModeConfig for that display. So that
+        // later we check if the policy mode has changed for the same display in policy.
+        // If mPolicy mode isn't available then we take the first display from the best display
+        // modes as the candidate for policy changes and frame rate overrides.
+        // TODO(b/240743786) Update the single display based assumptions and make mode changes
+        // and mPolicy per display.
+        const DisplayModeConfig& displayModeConfigForCurrentPolicy = mPolicy.mode
+                ? *std::find_if(displayModeConfigs.begin(), displayModeConfigs.end(),
+                                [&](const auto& displayModeConfig) REQUIRES(mPolicyLock) {
+                                    return displayModeConfig.displayModePtr
+                                                   ->getPhysicalDisplayId() ==
+                                            mPolicy.mode->getPhysicalDisplayId();
+                                })
+                : displayModeConfigs.front();
+
+        newMode = displayModeConfigForCurrentPolicy.displayModePtr;
+        consideredSignals = displayModeConfigForCurrentPolicy.signals;
         frameRateOverridesChanged = updateFrameRateOverrides(consideredSignals, newMode->getFps());
 
         if (mPolicy.mode == newMode) {
@@ -691,9 +743,7 @@
         }
     }
     if (refreshRateChanged) {
-        mSchedulerCallback.requestDisplayMode(std::move(newMode),
-                                              consideredSignals.idle ? DisplayModeEvent::None
-                                                                     : DisplayModeEvent::Changed);
+        mSchedulerCallback.requestDisplayModes(std::move(displayModeConfigs));
     }
     if (frameRateOverridesChanged) {
         mSchedulerCallback.triggerOnFrameRateOverridesChanged();
@@ -701,12 +751,68 @@
     return consideredSignals;
 }
 
-auto Scheduler::getRankedDisplayModes()
-        -> std::pair<std::vector<RefreshRateRanking>, GlobalSignals> {
+void Scheduler::registerDisplay(const sp<const DisplayDevice>& display) {
+    const bool ok = mDisplays.try_emplace(display->getPhysicalId(), display).second;
+    ALOGE_IF(!ok, "Duplicate display registered");
+}
+
+void Scheduler::unregisterDisplay(PhysicalDisplayId displayId) {
+    mDisplays.erase(displayId);
+}
+
+std::vector<DisplayModeConfig> Scheduler::getBestDisplayModeConfigs() const {
     ATRACE_CALL();
 
-    const auto configs = holdRefreshRateConfigs();
+    std::vector<RefreshRateRankingsAndSignals> refreshRateRankingsAndSignalsPerDisplay;
+    refreshRateRankingsAndSignalsPerDisplay.reserve(mDisplays.size());
 
+    const auto displayModeSelectionParams = getDisplayModeSelectionParams();
+
+    std::for_each(mDisplays.begin(), mDisplays.end(), [&](const auto& display) {
+        const auto& [refreshRateRankings, globalSignals] =
+                display.second->holdRefreshRateConfigs()
+                        ->getRankedRefreshRates(displayModeSelectionParams.layerRequirements,
+                                                displayModeSelectionParams.globalSignals);
+        refreshRateRankingsAndSignalsPerDisplay.emplace_back(
+                RefreshRateRankingsAndSignals{refreshRateRankings, globalSignals});
+    });
+
+    // FPS and their Aggregated score.
+    std::unordered_map<Fps, AggregatedFpsScore, FpsHash, FpsApproxEqual> aggregatedScoresPerFps =
+            getAggregatedScoresPerFps(refreshRateRankingsAndSignalsPerDisplay);
+
+    Fps chosenFps = std::max_element(aggregatedScoresPerFps.begin(), aggregatedScoresPerFps.end(),
+                                     [](const auto& max, const auto& current) {
+                                         return max.second.totalScore <= current.second.totalScore;
+                                     })
+                            ->first;
+
+    return getDisplayModeConfigsForTheChosenFps(chosenFps, refreshRateRankingsAndSignalsPerDisplay);
+}
+
+std::vector<DisplayModeConfig> Scheduler::getDisplayModeConfigsForTheChosenFps(
+        Fps chosenFps,
+        const std::vector<RefreshRateRankingsAndSignals>& refreshRateRankingsAndSignalsPerDisplay)
+        const {
+    std::vector<DisplayModeConfig> displayModeConfigs;
+    displayModeConfigs.reserve(mDisplays.size());
+    using fps_approx_ops::operator==;
+    std::for_each(refreshRateRankingsAndSignalsPerDisplay.begin(),
+                  refreshRateRankingsAndSignalsPerDisplay.end(),
+                  [&](const auto& refreshRateRankingsAndSignal) {
+                      for (const auto& ranking : refreshRateRankingsAndSignal.refreshRateRankings) {
+                          if (ranking.displayModePtr->getFps() == chosenFps) {
+                              displayModeConfigs.emplace_back(
+                                      DisplayModeConfig{refreshRateRankingsAndSignal.globalSignals,
+                                                        ranking.displayModePtr});
+                              break;
+                          }
+                      }
+                  });
+    return displayModeConfigs;
+}
+
+DisplayModeSelectionParams Scheduler::getDisplayModeSelectionParams() const {
     const bool powerOnImminent = mDisplayPowerTimer &&
             (mPolicy.displayPowerMode != hal::PowerMode::ON ||
              mPolicy.displayPowerTimer == TimerState::Reset);
@@ -715,7 +821,18 @@
                                 .idle = mPolicy.idleTimer == TimerState::Expired,
                                 .powerOnImminent = powerOnImminent};
 
-    return configs->getRankedRefreshRates(mPolicy.contentRequirements, signals);
+    return {mPolicy.contentRequirements, signals};
+}
+
+auto Scheduler::getRankedDisplayModes()
+        -> std::pair<std::vector<RefreshRateRanking>, GlobalSignals> {
+    ATRACE_CALL();
+
+    const auto configs = holdRefreshRateConfigs();
+
+    const auto displayModeSelectionParams = getDisplayModeSelectionParams();
+    return configs->getRankedRefreshRates(displayModeSelectionParams.layerRequirements,
+                                          displayModeSelectionParams.globalSignals);
 }
 
 DisplayModePtr Scheduler::getPreferredDisplayMode() {
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index f567205..d6f62ca 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -24,6 +24,7 @@
 #include <mutex>
 #include <optional>
 #include <unordered_map>
+#include <utility>
 
 // TODO(b/129481165): remove the #pragma below and fix conversion issues
 #pragma clang diagnostic push
@@ -32,9 +33,11 @@
 #include <ui/GraphicTypes.h>
 #pragma clang diagnostic pop // ignored "-Wconversion -Wextra"
 
+#include <DisplayDevice.h>
 #include <scheduler/Features.h>
 #include <scheduler/Time.h>
 
+#include "Display/DisplayMap.h"
 #include "EventThread.h"
 #include "FrameRateOverrideMappings.h"
 #include "LayerHistory.h"
@@ -83,11 +86,22 @@
 
 namespace scheduler {
 
+using GlobalSignals = RefreshRateConfigs::GlobalSignals;
+
+// Config representing the DisplayMode and considered signals for the Display.
+struct DisplayModeConfig {
+    const GlobalSignals signals;
+    const DisplayModePtr displayModePtr;
+
+    DisplayModeConfig(GlobalSignals signals, DisplayModePtr displayModePtr)
+          : signals(signals), displayModePtr(std::move(displayModePtr)) {}
+};
+
 struct ISchedulerCallback {
     using DisplayModeEvent = scheduler::DisplayModeEvent;
 
     virtual void setVsyncEnabled(bool) = 0;
-    virtual void requestDisplayMode(DisplayModePtr, DisplayModeEvent) = 0;
+    virtual void requestDisplayModes(std::vector<DisplayModeConfig>) = 0;
     virtual void kernelTimerChanged(bool expired) = 0;
     virtual void triggerOnFrameRateOverridesChanged() = 0;
 
@@ -95,6 +109,25 @@
     ~ISchedulerCallback() = default;
 };
 
+// Holds the total score of the FPS and
+// number of displays the FPS is found in.
+struct AggregatedFpsScore {
+    float totalScore;
+    size_t numDisplays;
+};
+
+// Represents LayerRequirements and GlobalSignals to be considered for the display mode selection.
+struct DisplayModeSelectionParams {
+    std::vector<RefreshRateConfigs::LayerRequirement> layerRequirements;
+    GlobalSignals globalSignals;
+};
+
+// Represents the RefreshRateRankings and GlobalSignals for the selected RefreshRateRankings.
+struct RefreshRateRankingsAndSignals {
+    std::vector<RefreshRateRanking> refreshRateRankings;
+    GlobalSignals globalSignals;
+};
+
 class Scheduler : android::impl::MessageQueue {
     using Impl = android::impl::MessageQueue;
 
@@ -237,6 +270,9 @@
         return mLayerHistory.getLayerFramerate(now, id);
     }
 
+    void registerDisplay(const sp<const DisplayDevice>&);
+    void unregisterDisplay(PhysicalDisplayId);
+
 private:
     friend class TestableScheduler;
 
@@ -260,8 +296,6 @@
 
     void setVsyncPeriod(nsecs_t period);
 
-    using GlobalSignals = RefreshRateConfigs::GlobalSignals;
-
     struct Policy;
 
     // Sets the S state of the policy to the T value under mPolicyLock, and chooses a display mode
@@ -274,6 +308,17 @@
     std::pair<std::vector<RefreshRateRanking>, GlobalSignals> getRankedDisplayModes()
             REQUIRES(mPolicyLock);
 
+    // Returns the best display mode per display.
+    std::vector<DisplayModeConfig> getBestDisplayModeConfigs() const REQUIRES(mPolicyLock);
+
+    // Returns the list of DisplayModeConfigs per display for the chosenFps.
+    std::vector<DisplayModeConfig> getDisplayModeConfigsForTheChosenFps(
+            Fps chosenFps, const std::vector<RefreshRateRankingsAndSignals>&) const;
+
+    // Returns the DisplayModeSelectionParams to be considered for the
+    // DisplayMode selection based on the current Policy and GlobalSignals.
+    DisplayModeSelectionParams getDisplayModeSelectionParams() const REQUIRES(mPolicyLock);
+
     bool updateFrameRateOverrides(GlobalSignals, Fps displayRefreshRate) REQUIRES(mPolicyLock);
 
     void dispatchCachedReportedMode() REQUIRES(mPolicyLock) EXCLUDES(mRefreshRateConfigsLock);
@@ -323,6 +368,10 @@
 
     mutable std::mutex mPolicyLock;
 
+    // Holds the Physical displays registered through the SurfaceFlinger, used for making
+    // the refresh rate selections.
+    display::PhysicalDisplayMap<PhysicalDisplayId, const sp<const DisplayDevice>> mDisplays;
+
     struct Policy {
         // Policy for choosing the display mode.
         LayerHistory::Summary contentRequirements;
diff --git a/services/surfaceflinger/Scheduler/include/scheduler/Fps.h b/services/surfaceflinger/Scheduler/include/scheduler/Fps.h
index bd4f409..2c77142 100644
--- a/services/surfaceflinger/Scheduler/include/scheduler/Fps.h
+++ b/services/surfaceflinger/Scheduler/include/scheduler/Fps.h
@@ -138,6 +138,10 @@
     bool operator()(Fps lhs, Fps rhs) const { return isApproxEqual(lhs, rhs); }
 };
 
+struct FpsHash {
+    size_t operator()(Fps fps) const { return std::hash<nsecs_t>()(fps.getPeriodNsecs()); }
+};
+
 inline std::string to_string(Fps fps) {
     return base::StringPrintf("%.2f Hz", fps.getValue());
 }
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 450594d..2d29e4c 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2938,7 +2938,7 @@
         if (display->isPrimary()) {
             mScheduler->setRefreshRateConfigs(display->holdRefreshRateConfigs());
         }
-
+        mScheduler->registerDisplay(display);
         dispatchDisplayHotplugEvent(display->getPhysicalId(), true);
     }
 
@@ -2954,6 +2954,7 @@
             releaseVirtualDisplay(display->getVirtualId());
         } else {
             dispatchDisplayHotplugEvent(display->getPhysicalId(), false);
+            mScheduler->unregisterDisplay(display->getPhysicalId());
         }
     }
 
@@ -2990,6 +2991,8 @@
             display->disconnect();
             if (display->isVirtual()) {
                 releaseVirtualDisplay(display->getVirtualId());
+            } else {
+                mScheduler->unregisterDisplay(display->getPhysicalId());
             }
         }
 
@@ -3319,25 +3322,34 @@
     mCompositionEngine->updateCursorAsync(refreshArgs);
 }
 
-void SurfaceFlinger::requestDisplayMode(DisplayModePtr mode, DisplayModeEvent event) {
+void SurfaceFlinger::requestDisplayModes(
+        std::vector<scheduler::DisplayModeConfig> displayModeConfigs) {
+    if (mBootStage != BootStage::FINISHED) {
+        ALOGV("Currently in the boot stage, skipping display mode changes");
+        return;
+    }
+
+    ATRACE_CALL();
     // If this is called from the main thread mStateLock must be locked before
     // Currently the only way to call this function from the main thread is from
     // Scheduler::chooseRefreshRateForContent
 
     ConditionalLock lock(mStateLock, std::this_thread::get_id() != mMainThreadId);
 
-    const auto display = getDefaultDisplayDeviceLocked();
-    if (!display || mBootStage != BootStage::FINISHED) {
-        return;
-    }
-    ATRACE_CALL();
-
-    if (!display->refreshRateConfigs().isModeAllowed(mode->getId())) {
-        ALOGV("Skipping disallowed mode %d", mode->getId().value());
-        return;
-    }
-
-    setDesiredActiveMode({std::move(mode), event});
+    std::for_each(displayModeConfigs.begin(), displayModeConfigs.end(),
+                  [&](const auto& config) REQUIRES(mStateLock) {
+                      const auto& displayModePtr = config.displayModePtr;
+                      if (const auto display =
+                                  getDisplayDeviceLocked(displayModePtr->getPhysicalDisplayId());
+                          display->refreshRateConfigs().isModeAllowed(displayModePtr->getId())) {
+                          const auto event = config.signals.idle ? DisplayModeEvent::None
+                                                                 : DisplayModeEvent::Changed;
+                          setDesiredActiveMode({displayModePtr, event});
+                      } else {
+                          ALOGV("Skipping disallowed mode %d for display %" PRId64,
+                                displayModePtr->getId().value(), display->getPhysicalId().value);
+                      }
+                  });
 }
 
 void SurfaceFlinger::triggerOnFrameRateOverridesChanged() {
@@ -3386,6 +3398,7 @@
 
         mScheduler->createVsyncSchedule(features);
         mScheduler->setRefreshRateConfigs(std::move(configs));
+        mScheduler->registerDisplay(display);
     }
     setVsyncEnabled(false);
     mScheduler->startTimers();
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 99d3736..426e788 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -631,8 +631,8 @@
 
     // Toggles hardware VSYNC by calling into HWC.
     void setVsyncEnabled(bool) override;
-    // Sets the desired display mode if allowed by policy.
-    void requestDisplayMode(DisplayModePtr, DisplayModeEvent) override;
+    // Sets the desired display mode per display if allowed by policy .
+    void requestDisplayModes(std::vector<scheduler::DisplayModeConfig>) override;
     // Called when kernel idle timer has expired. Used to update the refresh rate overlay.
     void kernelTimerChanged(bool expired) override;
     // Called when the frame rate override list changed to trigger an event.
diff --git a/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h b/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h
index 72b6cc9..0b21272 100644
--- a/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h
+++ b/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h
@@ -781,7 +781,7 @@
 
 private:
     void setVsyncEnabled(bool) override {}
-    void requestDisplayMode(DisplayModePtr, DisplayModeEvent) override {}
+    void requestDisplayModes(std::vector<scheduler::DisplayModeConfig>) override {}
     void kernelTimerChanged(bool) override {}
     void triggerOnFrameRateOverridesChanged() override {}
 
diff --git a/services/surfaceflinger/tests/unittests/FakeDisplayInjector.h b/services/surfaceflinger/tests/unittests/FakeDisplayInjector.h
new file mode 100644
index 0000000..81b420c
--- /dev/null
+++ b/services/surfaceflinger/tests/unittests/FakeDisplayInjector.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <gmock/gmock.h>
+
+#include "TestableSurfaceFlinger.h"
+#include "mock/DisplayHardware/MockPowerAdvisor.h"
+#include "mock/system/window/MockNativeWindow.h"
+
+namespace android {
+
+using FakeDisplayDeviceInjector = TestableSurfaceFlinger::FakeDisplayDeviceInjector;
+using android::hardware::graphics::composer::hal::HWDisplayId;
+using android::Hwc2::mock::PowerAdvisor;
+using testing::_;
+using testing::AnyNumber;
+using testing::DoAll;
+using testing::Mock;
+using testing::ResultOf;
+using testing::Return;
+using testing::SetArgPointee;
+
+class FakeDisplayInjector {
+public:
+    sp<DisplayDevice> injectDefaultInternalDisplay(
+            const std::function<void(FakeDisplayDeviceInjector&)>& injectExtra,
+            TestableSurfaceFlinger& flinger, uint8_t port = 255u) const {
+        constexpr int DEFAULT_DISPLAY_WIDTH = 1080;
+        constexpr int DEFAULT_DISPLAY_HEIGHT = 1920;
+        constexpr HWDisplayId DEFAULT_DISPLAY_HWC_DISPLAY_ID = 0;
+
+        const PhysicalDisplayId physicalDisplayId = PhysicalDisplayId::fromPort(port);
+
+        // The DisplayDevice is required to have a framebuffer (behind the
+        // ANativeWindow interface) which uses the actual hardware display
+        // size.
+        EXPECT_CALL(*mNativeWindow, query(NATIVE_WINDOW_WIDTH, _))
+                .WillRepeatedly(DoAll(SetArgPointee<1>(DEFAULT_DISPLAY_WIDTH), Return(0)));
+        EXPECT_CALL(*mNativeWindow, query(NATIVE_WINDOW_HEIGHT, _))
+                .WillRepeatedly(DoAll(SetArgPointee<1>(DEFAULT_DISPLAY_HEIGHT), Return(0)));
+        EXPECT_CALL(*mNativeWindow, perform(NATIVE_WINDOW_SET_BUFFERS_FORMAT));
+        EXPECT_CALL(*mNativeWindow, perform(NATIVE_WINDOW_API_CONNECT));
+        EXPECT_CALL(*mNativeWindow, perform(NATIVE_WINDOW_SET_USAGE64));
+        EXPECT_CALL(*mNativeWindow, perform(NATIVE_WINDOW_API_DISCONNECT)).Times(AnyNumber());
+
+        auto compositionDisplay = compositionengine::impl::
+                createDisplay(flinger.getCompositionEngine(),
+                              compositionengine::DisplayCreationArgsBuilder()
+                                      .setId(physicalDisplayId)
+                                      .setPixels({DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT})
+                                      .setPowerAdvisor(mPowerAdvisor)
+                                      .build());
+
+        constexpr bool kIsPrimary = true;
+        auto injector = FakeDisplayDeviceInjector(flinger, compositionDisplay,
+                                                  ui::DisplayConnectionType::Internal,
+                                                  DEFAULT_DISPLAY_HWC_DISPLAY_ID, kIsPrimary);
+
+        injector.setNativeWindow(mNativeWindow);
+        if (injectExtra) {
+            injectExtra(injector);
+        }
+
+        auto displayDevice = injector.inject();
+
+        Mock::VerifyAndClear(mNativeWindow.get());
+
+        return displayDevice;
+    }
+
+    sp<mock::NativeWindow> mNativeWindow = sp<mock::NativeWindow>::make();
+    PowerAdvisor* mPowerAdvisor = new PowerAdvisor();
+};
+
+} // namespace android
\ No newline at end of file
diff --git a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
index 53e49eb..8d2130f 100644
--- a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
@@ -20,6 +20,7 @@
 
 #include <mutex>
 
+#include "FakeDisplayInjector.h"
 #include "Scheduler/EventThread.h"
 #include "Scheduler/RefreshRateConfigs.h"
 #include "TestableScheduler.h"
@@ -40,6 +41,7 @@
 
 using MockEventThread = android::mock::EventThread;
 using MockLayer = android::mock::MockLayer;
+using FakeDisplayDeviceInjector = TestableSurfaceFlinger::FakeDisplayDeviceInjector;
 
 constexpr PhysicalDisplayId PHYSICAL_DISPLAY_ID = PhysicalDisplayId::fromPort(255u);
 
@@ -59,11 +61,13 @@
 
     SchedulerTest();
 
-    static inline const DisplayModePtr kMode60 = createDisplayMode(DisplayModeId(0), 60_Hz);
-    static inline const DisplayModePtr kMode120 = createDisplayMode(DisplayModeId(1), 120_Hz);
+    static inline const DisplayModePtr kMode60_1 = createDisplayMode(DisplayModeId(0), 60_Hz);
+    static inline const DisplayModePtr kMode120_1 = createDisplayMode(DisplayModeId(1), 120_Hz);
+    static inline const DisplayModePtr kMode60_2 = createDisplayMode(DisplayModeId(2), 60_Hz);
+    static inline const DisplayModePtr kMode120_2 = createDisplayMode(DisplayModeId(3), 120_Hz);
 
     std::shared_ptr<RefreshRateConfigs> mConfigs =
-            std::make_shared<RefreshRateConfigs>(makeModes(kMode60), kMode60->getId());
+            std::make_shared<RefreshRateConfigs>(makeModes(kMode60_1), kMode60_1->getId());
 
     mock::SchedulerCallback mSchedulerCallback;
     TestableScheduler* mScheduler = new TestableScheduler{mConfigs, mSchedulerCallback};
@@ -71,6 +75,7 @@
     ConnectionHandle mConnectionHandle;
     MockEventThread* mEventThread;
     sp<MockEventThreadConnection> mEventThreadConnection;
+    FakeDisplayInjector mFakeDisplayInjector;
 
     TestableSurfaceFlinger mFlinger;
 };
@@ -166,7 +171,7 @@
     constexpr uint32_t kDisplayArea = 999'999;
     mScheduler->onActiveDisplayAreaChanged(kDisplayArea);
 
-    EXPECT_CALL(mSchedulerCallback, requestDisplayMode(_, _)).Times(0);
+    EXPECT_CALL(mSchedulerCallback, requestDisplayModes(_)).Times(0);
     mScheduler->chooseRefreshRateForContent();
 }
 
@@ -176,7 +181,8 @@
     ASSERT_EQ(1u, mScheduler->layerHistorySize());
 
     mScheduler->setRefreshRateConfigs(
-            std::make_shared<RefreshRateConfigs>(makeModes(kMode60, kMode120), kMode60->getId()));
+            std::make_shared<RefreshRateConfigs>(makeModes(kMode60_1, kMode120_1),
+                                                 kMode60_1->getId()));
 
     ASSERT_EQ(0u, mScheduler->getNumActiveLayers());
     mScheduler->recordLayerHistory(layer.get(), 0, LayerHistory::LayerUpdateType::Buffer);
@@ -215,12 +221,18 @@
 }
 
 MATCHER(Is120Hz, "") {
-    return isApproxEqual(arg->getFps(), 120_Hz);
+    return isApproxEqual(arg.front().displayModePtr->getFps(), 120_Hz);
 }
 
 TEST_F(SchedulerTest, chooseRefreshRateForContentSelectsMaxRefreshRate) {
-    mScheduler->setRefreshRateConfigs(
-            std::make_shared<RefreshRateConfigs>(makeModes(kMode60, kMode120), kMode60->getId()));
+    auto display = mFakeDisplayInjector.injectDefaultInternalDisplay(
+            [&](FakeDisplayDeviceInjector& injector) {
+                injector.setDisplayModes(makeModes(kMode60_1, kMode120_1), kMode60_1->getId());
+            },
+            mFlinger);
+
+    mScheduler->registerDisplay(display);
+    mScheduler->setRefreshRateConfigs(display->holdRefreshRateConfigs());
 
     const sp<MockLayer> layer = sp<MockLayer>::make(mFlinger.flinger());
     EXPECT_CALL(*layer, isVisible()).WillOnce(Return(true));
@@ -233,12 +245,111 @@
     constexpr uint32_t kDisplayArea = 999'999;
     mScheduler->onActiveDisplayAreaChanged(kDisplayArea);
 
-    EXPECT_CALL(mSchedulerCallback, requestDisplayMode(Is120Hz(), _)).Times(1);
+    EXPECT_CALL(mSchedulerCallback, requestDisplayModes(Is120Hz())).Times(1);
     mScheduler->chooseRefreshRateForContent();
 
     // No-op if layer requirements have not changed.
-    EXPECT_CALL(mSchedulerCallback, requestDisplayMode(_, _)).Times(0);
+    EXPECT_CALL(mSchedulerCallback, requestDisplayModes(_)).Times(0);
     mScheduler->chooseRefreshRateForContent();
 }
 
+TEST_F(SchedulerTest, getBestDisplayMode_singleDisplay) {
+    auto display = mFakeDisplayInjector.injectDefaultInternalDisplay(
+            [&](FakeDisplayDeviceInjector& injector) {
+                injector.setDisplayModes(makeModes(kMode60_1, kMode120_1), kMode60_1->getId());
+            },
+            mFlinger);
+    mScheduler->registerDisplay(display);
+
+    std::vector<RefreshRateConfigs::LayerRequirement> layers =
+            std::vector<RefreshRateConfigs::LayerRequirement>({{.weight = 1.f}, {.weight = 1.f}});
+    mScheduler->setContentRequirements(layers);
+    GlobalSignals globalSignals = {.idle = true};
+    mScheduler->setTouchStateAndIdleTimerPolicy(globalSignals);
+
+    std::vector<DisplayModeConfig> displayModeConfigs = mScheduler->getBestDisplayModeConfigs();
+    ASSERT_EQ(1ul, displayModeConfigs.size());
+    EXPECT_EQ(displayModeConfigs.front().displayModePtr, kMode60_1);
+    EXPECT_EQ(displayModeConfigs.front().signals, globalSignals);
+
+    globalSignals = {.idle = false};
+    mScheduler->setTouchStateAndIdleTimerPolicy(globalSignals);
+    displayModeConfigs = mScheduler->getBestDisplayModeConfigs();
+    ASSERT_EQ(1ul, displayModeConfigs.size());
+    EXPECT_EQ(displayModeConfigs.front().displayModePtr, kMode120_1);
+    EXPECT_EQ(displayModeConfigs.front().signals, globalSignals);
+
+    globalSignals = {.touch = true};
+    mScheduler->replaceTouchTimer(10);
+    mScheduler->setTouchStateAndIdleTimerPolicy(globalSignals);
+    displayModeConfigs = mScheduler->getBestDisplayModeConfigs();
+    ASSERT_EQ(1ul, displayModeConfigs.size());
+    EXPECT_EQ(displayModeConfigs.front().displayModePtr, kMode120_1);
+    EXPECT_EQ(displayModeConfigs.front().signals, globalSignals);
+
+    mScheduler->unregisterDisplay(display->getPhysicalId());
+    EXPECT_TRUE(mScheduler->mutableDisplays().empty());
+}
+
+TEST_F(SchedulerTest, getBestDisplayModes_multipleDisplays) {
+    auto display1 = mFakeDisplayInjector.injectDefaultInternalDisplay(
+            [&](FakeDisplayDeviceInjector& injector) {
+                injector.setDisplayModes(makeModes(kMode60_1, kMode120_1), kMode60_1->getId());
+            },
+            mFlinger);
+    auto display2 = mFakeDisplayInjector.injectDefaultInternalDisplay(
+            [&](FakeDisplayDeviceInjector& injector) {
+                injector.setDisplayModes(makeModes(kMode60_2, kMode120_2), kMode60_2->getId());
+            },
+            mFlinger, /* port */ 253u);
+    mScheduler->registerDisplay(display1);
+    mScheduler->registerDisplay(display2);
+
+    const std::vector<sp<DisplayDevice>>& expectedDisplays = {display1, display2};
+    std::vector<RefreshRateConfigs::LayerRequirement> layers = {{.weight = 1.f}, {.weight = 1.f}};
+    GlobalSignals globalSignals = {.idle = true};
+    std::vector<DisplayModeConfig> expectedConfigs = {DisplayModeConfig{globalSignals, kMode60_1},
+                                                      DisplayModeConfig{globalSignals, kMode60_2}};
+
+    mScheduler->setContentRequirements(layers);
+    mScheduler->setTouchStateAndIdleTimerPolicy(globalSignals);
+    std::vector<DisplayModeConfig> displayModeConfigs = mScheduler->getBestDisplayModeConfigs();
+    ASSERT_EQ(displayModeConfigs.size(), expectedConfigs.size());
+    for (size_t i = 0; i < expectedConfigs.size(); ++i) {
+        EXPECT_EQ(expectedConfigs.at(i).displayModePtr, displayModeConfigs.at(i).displayModePtr)
+                << "Expected fps " << expectedConfigs.at(i).displayModePtr->getFps().getIntValue()
+                << " Actual fps "
+                << displayModeConfigs.at(i).displayModePtr->getFps().getIntValue();
+        EXPECT_EQ(globalSignals, displayModeConfigs.at(i).signals);
+    }
+
+    expectedConfigs = std::vector<DisplayModeConfig>{DisplayModeConfig{globalSignals, kMode120_1},
+                                                     DisplayModeConfig{globalSignals, kMode120_2}};
+
+    globalSignals = {.idle = false};
+    mScheduler->setTouchStateAndIdleTimerPolicy(globalSignals);
+    displayModeConfigs = mScheduler->getBestDisplayModeConfigs();
+    ASSERT_EQ(expectedConfigs.size(), displayModeConfigs.size());
+    for (size_t i = 0; i < expectedConfigs.size(); ++i) {
+        EXPECT_EQ(expectedConfigs.at(i).displayModePtr, displayModeConfigs.at(i).displayModePtr)
+                << "Expected fps " << expectedConfigs.at(i).displayModePtr->getFps().getIntValue()
+                << " Actual fps "
+                << displayModeConfigs.at(i).displayModePtr->getFps().getIntValue();
+        EXPECT_EQ(globalSignals, displayModeConfigs.at(i).signals);
+    }
+
+    globalSignals = {.touch = true};
+    mScheduler->replaceTouchTimer(10);
+    mScheduler->setTouchStateAndIdleTimerPolicy(globalSignals);
+    displayModeConfigs = mScheduler->getBestDisplayModeConfigs();
+    ASSERT_EQ(expectedConfigs.size(), displayModeConfigs.size());
+    for (size_t i = 0; i < expectedConfigs.size(); ++i) {
+        EXPECT_EQ(expectedConfigs.at(i).displayModePtr, displayModeConfigs.at(i).displayModePtr)
+                << "Expected fps " << expectedConfigs.at(i).displayModePtr->getFps().getIntValue()
+                << " Actual fps "
+                << displayModeConfigs.at(i).displayModePtr->getFps().getIntValue();
+        EXPECT_EQ(globalSignals, displayModeConfigs.at(i).signals);
+    }
+}
+
 } // namespace android::scheduler
diff --git a/services/surfaceflinger/tests/unittests/SurfaceFlinger_NotifyPowerBoostTest.cpp b/services/surfaceflinger/tests/unittests/SurfaceFlinger_NotifyPowerBoostTest.cpp
index ec7e8a7..4e9f293 100644
--- a/services/surfaceflinger/tests/unittests/SurfaceFlinger_NotifyPowerBoostTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SurfaceFlinger_NotifyPowerBoostTest.cpp
@@ -21,6 +21,7 @@
 #include <thread>
 
 #include "DisplayTransactionTestHelpers.h"
+#include "FakeDisplayInjector.h"
 
 #include <android/hardware/power/Boost.h>
 
@@ -32,6 +33,8 @@
 TEST_F(DisplayTransactionTest, notifyPowerBoostNotifiesTouchEvent) {
     using namespace std::chrono_literals;
 
+    injectDefaultInternalDisplay([](FakeDisplayDeviceInjector&) {});
+
     mFlinger.scheduler()->replaceTouchTimer(100);
     std::this_thread::sleep_for(10ms);                  // wait for callback to be triggered
     EXPECT_TRUE(mFlinger.scheduler()->isTouchActive()); // Starting timer activates touch
diff --git a/services/surfaceflinger/tests/unittests/TestableScheduler.h b/services/surfaceflinger/tests/unittests/TestableScheduler.h
index 93e3059..68df987 100644
--- a/services/surfaceflinger/tests/unittests/TestableScheduler.h
+++ b/services/surfaceflinger/tests/unittests/TestableScheduler.h
@@ -68,6 +68,8 @@
 
     auto& mutableLayerHistory() { return mLayerHistory; }
 
+    auto& mutableDisplays() { return mDisplays; }
+
     size_t layerHistorySize() NO_THREAD_SAFETY_ANALYSIS {
         return mLayerHistory.mActiveLayerInfos.size() + mLayerHistory.mInactiveLayerInfos.size();
     }
@@ -94,6 +96,22 @@
         return mPolicy.touch == Scheduler::TouchState::Active;
     }
 
+    void setTouchStateAndIdleTimerPolicy(GlobalSignals globalSignals) {
+        std::lock_guard<std::mutex> lock(mPolicyLock);
+        mPolicy.touch = globalSignals.touch ? TouchState::Active : TouchState::Inactive;
+        mPolicy.idleTimer = globalSignals.idle ? TimerState::Expired : TimerState::Reset;
+    }
+
+    void setContentRequirements(std::vector<RefreshRateConfigs::LayerRequirement> layers) {
+        std::lock_guard<std::mutex> lock(mPolicyLock);
+        mPolicy.contentRequirements = std::move(layers);
+    }
+
+    std::vector<DisplayModeConfig> getBestDisplayModeConfigs() {
+        std::lock_guard<std::mutex> lock(mPolicyLock);
+        return Scheduler::getBestDisplayModeConfigs();
+    }
+
     void dispatchCachedReportedMode() {
         std::lock_guard<std::mutex> lock(mPolicyLock);
         return Scheduler::dispatchCachedReportedMode();
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 5338f4a..f5042d3 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -842,6 +842,9 @@
 
             sp<DisplayDevice> display = sp<DisplayDevice>::make(mCreationArgs);
             mFlinger.mutableDisplays().emplace_or_replace(mDisplayToken, display);
+            if (mFlinger.scheduler()) {
+                mFlinger.scheduler()->registerDisplay(display);
+            }
 
             DisplayDeviceState state;
             state.isSecure = mCreationArgs.isSecure;
diff --git a/services/surfaceflinger/tests/unittests/mock/MockSchedulerCallback.h b/services/surfaceflinger/tests/unittests/mock/MockSchedulerCallback.h
index 5267586..8af2dfa 100644
--- a/services/surfaceflinger/tests/unittests/mock/MockSchedulerCallback.h
+++ b/services/surfaceflinger/tests/unittests/mock/MockSchedulerCallback.h
@@ -24,14 +24,14 @@
 
 struct SchedulerCallback final : ISchedulerCallback {
     MOCK_METHOD(void, setVsyncEnabled, (bool), (override));
-    MOCK_METHOD(void, requestDisplayMode, (DisplayModePtr, DisplayModeEvent), (override));
+    MOCK_METHOD(void, requestDisplayModes, (std::vector<scheduler::DisplayModeConfig>), (override));
     MOCK_METHOD(void, kernelTimerChanged, (bool), (override));
     MOCK_METHOD(void, triggerOnFrameRateOverridesChanged, (), (override));
 };
 
 struct NoOpSchedulerCallback final : ISchedulerCallback {
     void setVsyncEnabled(bool) override {}
-    void requestDisplayMode(DisplayModePtr, DisplayModeEvent) override {}
+    void requestDisplayModes(std::vector<scheduler::DisplayModeConfig>) override {}
     void kernelTimerChanged(bool) override {}
     void triggerOnFrameRateOverridesChanged() override {}
 };