Android13 SurfaceFlinger启动流程分析-CSDN博客

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//frameworks/native/services/surfaceflinger/SurfaceFlinger.rc
service surfaceflinger /system/bin/surfaceflinger
    class core animation
    user system
    group graphics drmrpc readproc
    capabilities SYS_NICE
    onrestart restart --only-if-running zygote
    task_profiles HighPerformance
    socket pdx/system/vr/display/client     stream 0666 system graphics u:object_r:pdx_display_client_endpoint_socket:s0
    socket pdx/system/vr/display/manager    stream 0666 system graphics u:object_r:pdx_display_manager_endpoint_socket:s0
    socket pdx/system/vr/display/vsync      stream 0666 system graphics u:object_r:pdx_display_vsync_endpoint_socket:s0
 
 
on property:vendor.debug.sf.restart=1
     restart surfaceflinger
 
 
on property:init.svc.zygote=restarting && property:debug.sf.toomanylayers=1
     restart surfaceflinger
     setprop debug.sf.toomanylayers "0"

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//frameworks/native/services/surfacefilinger/main_SurfaceFlinger.cpp
int main(int, char**) {
    signal(SIGPIPE, SIG_IGN);
 
 
    hardware::configureRpcThreadpool(1 /* maxThreads */,
            false /* callerWillJoin */);
 
 
    startGraphicsAllocatorService();
 
 
    // When SF is launched in its own process, limit the number of
    // binder threads to 4.
    ProcessState::self()->setThreadPoolMaxThreadCount(4);
 
 
    // Set uclamp.min setting on all threads, maybe an overkill but we want
    // to cover important threads like RenderEngine.
    if (SurfaceFlinger::setSchedAttr(true) != NO_ERROR) {
        ALOGW("Couldn't set uclamp.min: %s\n", strerror(errno));
    }
 
 
    // The binder threadpool we start will inherit sched policy and priority
    // of (this) creating thread. We want the binder thread pool to have
    // SCHED_FIFO policy and priority 1 (lowest RT priority)
    // Once the pool is created we reset this thread's priority back to
    // original.
    int newPriority = 0;
    int origPolicy = sched_getscheduler(0);
    struct sched_param origSchedParam;
 
 
    int errorInPriorityModification = sched_getparam(0, &origSchedParam);
    if (errorInPriorityModification == 0) {
        int policy = SCHED_FIFO;
        newPriority = sched_get_priority_min(policy);
 
 
        struct sched_param param;
        param.sched_priority = newPriority;
 
 
        errorInPriorityModification = sched_setscheduler(0, policy, &param);
    }
 
 
    // start the thread pool
    //构建ProcessState全局对象gProcess，打开binder驱动，建立链接
    //在驱动内部创建该进程的binder_proc,binder_thread结构，保存该进程的进程信息和线程信息，并加入驱动的红黑树队列中。
    //获取驱动的版本信息，把该进程最多可同时启动的线程告诉驱动，并保存到改进程的binder_proc结构中
    //把设备文件/dev/binder映射到内存中
    sp<ProcessState> ps(ProcessState::self());
    ps->startThreadPool();
 
 
    // Reset current thread's policy and priority
    if (errorInPriorityModification == 0) {
        errorInPriorityModification = sched_setscheduler(0, origPolicy, &origSchedParam);
    } else {
        ALOGE("Failed to set SurfaceFlinger binder threadpool priority to SCHED_FIFO");
    }
 
 
    // instantiate surfaceflinger
    // 实例化surfaceflinger
    sp<SurfaceFlinger> flinger = surfaceflinger::createSurfaceFlinger();
 
 
    // Set the minimum policy of surfaceflinger node to be SCHED_FIFO.
    // So any thread with policy/priority lower than {SCHED_FIFO, 1}, will run
    // at least with SCHED_FIFO policy and priority 1.
    if (errorInPriorityModification == 0) {
        flinger->setMinSchedulerPolicy(SCHED_FIFO, newPriority);
    }
 
 
    //设置优先级
    setpriority(PRIO_PROCESS, 0, PRIORITY_URGENT_DISPLAY);
 
 
    //把SF的自身调用限制在4线程
    set_sched_policy(0, SP_FOREGROUND);
 
 
    // Put most SurfaceFlinger threads in the system-background cpuset
    // Keeps us from unnecessarily using big cores
    // Do this after the binder thread pool init
    if (cpusets_enabled()) set_cpuset_policy(0, SP_SYSTEM);
 
 
    // initialize before clients can connect
    // 在客户端连接之前进行初始化
    flinger->init();
 
 
    // publish surface flinger
    // 将surfaceflinger放入servicemanager
    sp<IServiceManager> sm(defaultServiceManager());
    sm->addService(String16(SurfaceFlinger::getServiceName()), flinger, false,
                   IServiceManager::DUMP_FLAG_PRIORITY_CRITICAL | IServiceManager::DUMP_FLAG_PROTO);
 
 
    // publish gui::ISurfaceComposer, the new AIDL interface
    sp<SurfaceComposerAIDL> composerAIDL = new SurfaceComposerAIDL(flinger);
    sm->addService(String16("SurfaceFlingerAIDL"), composerAIDL, false,
                   IServiceManager::DUMP_FLAG_PRIORITY_CRITICAL | IServiceManager::DUMP_FLAG_PROTO);
 
 
    startDisplayService(); // dependency on SF getting registered above
 
 
    if (SurfaceFlinger::setSchedFifo(true) != NO_ERROR) {
        ALOGW("Couldn't set to SCHED_FIFO: %s", strerror(errno));
    }
 
 
    // run surface flinger in this thread
    // 运行surfaceflinger这个线程
    flinger->run();
 
 
    return 0;
}

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//frameworks/native/services/surfaceflinger/SurfaceflingerFactory.cpp
sp<SurfaceFlinger> createSurfaceFlinger() {
    static DefaultFactory factory;
    return new SurfaceFlinger(factory);
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
SurfaceFlinger::SurfaceFlinger(Factory& factory) : SurfaceFlinger(factory, SkipInitialization) {
    ALOGI("SurfaceFlinger is starting");
 
 
    hasSyncFramework = running_without_sync_framework(true);
 
 
    dispSyncPresentTimeOffset = present_time_offset_from_vsync_ns(0);
 
 
    useHwcForRgbToYuv = force_hwc_copy_for_virtual_displays(false);
 
 
    maxFrameBufferAcquiredBuffers = max_frame_buffer_acquired_buffers(2);
 
 
    maxGraphicsWidth = std::max(max_graphics_width(0), 0);
    maxGraphicsHeight = std::max(max_graphics_height(0), 0);
 
 
    hasWideColorDisplay = has_wide_color_display(false);
    mDefaultCompositionDataspace =
            static_cast<ui::Dataspace>(default_composition_dataspace(Dataspace::V0_SRGB));
    mWideColorGamutCompositionDataspace = static_cast<ui::Dataspace>(wcg_composition_dataspace(
            hasWideColorDisplay ? Dataspace::DISPLAY_P3 : Dataspace::V0_SRGB));
    defaultCompositionDataspace = mDefaultCompositionDataspace;
    wideColorGamutCompositionDataspace = mWideColorGamutCompositionDataspace;
    defaultCompositionPixelFormat = static_cast<ui::PixelFormat>(
            default_composition_pixel_format(ui::PixelFormat::RGBA_8888));
    wideColorGamutCompositionPixelFormat =
            static_cast<ui::PixelFormat>(wcg_composition_pixel_format(ui::PixelFormat::RGBA_8888));
 
 
    mColorSpaceAgnosticDataspace =
            static_cast<ui::Dataspace>(color_space_agnostic_dataspace(Dataspace::UNKNOWN));
 
 
    mLayerCachingEnabled = [] {
        const bool enable =
                android::sysprop::SurfaceFlingerProperties::enable_layer_caching().value_or(false);
        return base::GetBoolProperty(std::string("debug.sf.enable_layer_caching"), enable);
    }();
 
 
    useContextPriority = use_context_priority(true);
 
 
    mInternalDisplayPrimaries = sysprop::getDisplayNativePrimaries();
 
 
    // debugging stuff...
    char value[PROPERTY_VALUE_MAX];
 
 
    property_get("ro.bq.gpu_to_cpu_unsupported", value, "0");
    mGpuToCpuSupported = !atoi(value);
 
 
    property_get("ro.build.type", value, "user");
    mIsUserBuild = strcmp(value, "user") == 0;
 
 
    mDebugFlashDelay = base::GetUintProperty("debug.sf.showupdates"s, 0u);
 
 
    // DDMS debugging deprecated (b/120782499)
    property_get("debug.sf.ddms", value, "0");
    int debugDdms = atoi(value);
    ALOGI_IF(debugDdms, "DDMS debugging not supported");
 
 
    property_get("debug.sf.enable_gl_backpressure", value, "0");
    mPropagateBackpressureClientComposition = atoi(value);
    ALOGI_IF(mPropagateBackpressureClientComposition,
             "Enabling backpressure propagation for Client Composition");
 
 
    property_get("ro.surface_flinger.supports_background_blur", value, "0");
    bool supportsBlurs = atoi(value);
    mSupportsBlur = supportsBlurs;
    ALOGI_IF(!mSupportsBlur, "Disabling blur effects, they are not supported.");
    property_get("ro.sf.blurs_are_expensive", value, "0");
    mBlursAreExpensive = atoi(value);
 
 
    const size_t defaultListSize = ISurfaceComposer::MAX_LAYERS;
    auto listSize = property_get_int32("debug.sf.max_igbp_list_size", int32_t(defaultListSize));
    mMaxGraphicBufferProducerListSize = (listSize > 0) ? size_t(listSize) : defaultListSize;
    mGraphicBufferProducerListSizeLogThreshold =
            std::max(static_cast<int>(0.95 *
                                      static_cast<double>(mMaxGraphicBufferProducerListSize)),
                     1);
 
 
    property_get("debug.sf.luma_sampling", value, "1");
    mLumaSampling = atoi(value);
 
 
    property_get("debug.sf.disable_client_composition_cache", value, "0");
    mDisableClientCompositionCache = atoi(value);
 
 
    property_get("debug.sf.predict_hwc_composition_strategy", value, "1");
    mPredictCompositionStrategy = atoi(value);
 
 
    property_get("debug.sf.treat_170m_as_sRGB", value, "0");
    mTreat170mAsSrgb = atoi(value);
 
 
    // We should be reading 'persist.sys.sf.color_saturation' here
    // but since /data may be encrypted, we need to wait until after vold
    // comes online to attempt to read the property. The property is
    // instead read after the boot animation
 
 
    if (base::GetBoolProperty("debug.sf.treble_testing_override"s, false)) {
        // Without the override SurfaceFlinger cannot connect to HIDL
        // services that are not listed in the manifests.  Considered
        // deriving the setting from the set service name, but it
        // would be brittle if the name that's not 'default' is used
        // for production purposes later on.
        ALOGI("Enabling Treble testing override");
        android::hardware::details::setTrebleTestingOverride(true);
    }
 
 
    mRefreshRateOverlaySpinner = property_get_bool("sf.debug.show_refresh_rate_overlay_spinner", 0);
 
 
    if (!mIsUserBuild && base::GetBoolProperty("debug.sf.enable_transaction_tracing"s, true)) {
        mTransactionTracing.emplace();
    }
 
 
    mIgnoreHdrCameraLayers = ignore_hdr_camera_layers(false);
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::init() {
    ALOGI(  "SurfaceFlinger's main thread ready to run. "
            "Initializing graphics H/W...");
    Mutex::Autolock _l(mStateLock);
 
 
    // Get a RenderEngine for the given display / config (can't fail)
    // TODO(b/77156734): We need to stop casting and use HAL types when possible.
    // Sending maxFrameBufferAcquiredBuffers as the cache size is tightly tuned to single-display.
    //获取给定显示/配置的 RenderEngine，并且设置一些参数
    auto builder = renderengine::RenderEngineCreationArgs::Builder()
                           .setPixelFormat(static_cast<int32_t>(defaultCompositionPixelFormat))
                           .setImageCacheSize(maxFrameBufferAcquiredBuffers)
                           .setUseColorManagerment(useColorManagement)
                           .setEnableProtectedContext(enable_protected_contents(false))
                           .setPrecacheToneMapperShaderOnly(false)
                           .setSupportsBackgroundBlur(mSupportsBlur)
                           .setContextPriority(
                                   useContextPriority
                                           ? renderengine::RenderEngine::ContextPriority::REALTIME
                                           : renderengine::RenderEngine::ContextPriority::MEDIUM);
    if (auto type = chooseRenderEngineTypeViaSysProp()) {
        builder.setRenderEngineType(type.value());
    }
    mCompositionEngine->setRenderEngine(renderengine::RenderEngine::create(builder.build()));
    mMaxRenderTargetSize =
            std::min(getRenderEngine().getMaxTextureSize(), getRenderEngine().getMaxViewportDims());
 
 
    // Set SF main policy after initializing RenderEngine which has its own policy.
    if (!SetTaskProfiles(0, {"SFMainPolicy"})) {
        ALOGW("Failed to set main task profile");
    }
 
 
    mCompositionEngine->setTimeStats(mTimeStats);
    mCompositionEngine->setHwComposer(getFactory().createHWComposer(mHwcServiceName));
    mCompositionEngine->getHwComposer().setCallback(*this);
    ClientCache::getInstance().setRenderEngine(&getRenderEngine());
 
 
    enableLatchUnsignaledConfig = getLatchUnsignaledConfig();
 
 
    if (base::GetBoolProperty("debug.sf.enable_hwc_vds"s, false)) {
        enableHalVirtualDisplays(true);
    }
 
 
    // Process any initial hotplug and resulting display changes.
    processDisplayHotplugEventsLocked();
    const auto display = getDefaultDisplayDeviceLocked();
    LOG_ALWAYS_FATAL_IF(!display, "Missing primary display after registering composer callback.");
    const auto displayId = display->getPhysicalId();
    LOG_ALWAYS_FATAL_IF(!getHwComposer().isConnected(displayId),
                        "Primary display is disconnected.");
 
 
    // initialize our drawing state
    mDrawingState = mCurrentState;
 
 
    // set initial conditions (e.g. unblank default device)
    initializeDisplays();
 
 
    mPowerAdvisor->init();
 
 
    char primeShaderCache[PROPERTY_VALUE_MAX];
    property_get("service.sf.prime_shader_cache", primeShaderCache, "1");
    if (atoi(primeShaderCache)) {
        if (setSchedFifo(false) != NO_ERROR) {
            ALOGW("Can't set SCHED_OTHER for primeCache");
        }
 
 
        mRenderEnginePrimeCacheFuture = getRenderEngine().primeCache();
 
 
        if (setSchedFifo(true) != NO_ERROR) {
            ALOGW("Can't set SCHED_OTHER for primeCache");
        }
    }
 
 
    onActiveDisplaySizeChanged(display);
 
 
    // Inform native graphics APIs whether the present timestamp is supported:
 
 
    const bool presentFenceReliable =
            !getHwComposer().hasCapability(Capability::PRESENT_FENCE_IS_NOT_RELIABLE);
    mStartPropertySetThread = getFactory().createStartPropertySetThread(presentFenceReliable);
 
 
    if (mStartPropertySetThread->Start() != NO_ERROR) {
        ALOGE("Run StartPropertySetThread failed!");
    }
 
 
    ALOGV("Done initializing");
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::processDisplayHotplugEventsLocked() {
    for (const auto& event : mPendingHotplugEvents) {
        std::optional<DisplayIdentificationInfo> info =
                getHwComposer().onHotplug(event.hwcDisplayId, event.connection);
 
 
        if (!info) {
            continue;
        }
 
 
        const auto displayId = info->id;
        const auto token = mPhysicalDisplayTokens.get(displayId);
 
 
        if (event.connection == hal::Connection::CONNECTED) {
            auto [supportedModes, activeMode] = loadDisplayModes(displayId);
 
 
            if (!token) {
                ALOGV("Creating display %s", to_string(displayId).c_str());
 
 
                DisplayDeviceState state;
                state.physical = {.id = displayId,
                                  .type = getHwComposer().getDisplayConnectionType(displayId),
                                  .hwcDisplayId = event.hwcDisplayId,
                                  .deviceProductInfo = std::move(info->deviceProductInfo),
                                  .supportedModes = std::move(supportedModes),
                                  .activeMode = std::move(activeMode)};
                state.isSecure = true; // All physical displays are currently considered secure.
                state.displayName = std::move(info->name);
 
 
                sp<IBinder> token = new BBinder();
                mCurrentState.displays.add(token, state);
                mPhysicalDisplayTokens.try_emplace(displayId, std::move(token));
                mInterceptor->saveDisplayCreation(state);
            } else {
                ALOGV("Recreating display %s", to_string(displayId).c_str());
 
 
                auto& state = mCurrentState.displays.editValueFor(token->get());
                state.sequenceId = DisplayDeviceState{}.sequenceId; // Generate new sequenceId.
                state.physical->supportedModes = std::move(supportedModes);
                state.physical->activeMode = std::move(activeMode);
                if (getHwComposer().updatesDeviceProductInfoOnHotplugReconnect()) {
                    state.physical->deviceProductInfo = std::move(info->deviceProductInfo);
                }
            }
        } else {
            ALOGV("Removing display %s", to_string(displayId).c_str());
 
 
            if (const ssize_t index = mCurrentState.displays.indexOfKey(token->get()); index >= 0) {
                const DisplayDeviceState& state = mCurrentState.displays.valueAt(index);
                mInterceptor->saveDisplayDeletion(state.sequenceId);
                mCurrentState.displays.removeItemsAt(index);
            }
 
 
            mPhysicalDisplayTokens.erase(displayId);
        }
 
 
        processDisplayChangesLocked();
    }
 
 
    mPendingHotplugEvents.clear();
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::processDisplayChangesLocked() {
    // here we take advantage of Vector's copy-on-write semantics to
    // improve performance by skipping the transaction entirely when
    // know that the lists are identical
    const KeyedVector<wp<IBinder>, DisplayDeviceState>& curr(mCurrentState.displays);
    const KeyedVector<wp<IBinder>, DisplayDeviceState>& draw(mDrawingState.displays);
    if (!curr.isIdenticalTo(draw)) {
        mVisibleRegionsDirty = true;
 
 
        // find the displays that were removed
        // (ie: in drawing state but not in current state)
        // also handle displays that changed
        // (ie: displays that are in both lists)
        for (size_t i = 0; i < draw.size(); i++) {
            const wp<IBinder>& displayToken = draw.keyAt(i);
            const ssize_t j = curr.indexOfKey(displayToken);
            if (j < 0) {
                // in drawing state but not in current state
                processDisplayRemoved(displayToken);
            } else {
                // this display is in both lists. see if something changed.
                const DisplayDeviceState& currentState = curr[j];
                const DisplayDeviceState& drawingState = draw[i];
                processDisplayChanged(displayToken, currentState, drawingState);
            }
        }
 
 
        // find displays that were added
        // (ie: in current state but not in drawing state)
        for (size_t i = 0; i < curr.size(); i++) {
            const wp<IBinder>& displayToken = curr.keyAt(i);
            if (draw.indexOfKey(displayToken) < 0) {
                processDisplayAdded(displayToken, curr[i]);
            }
        }
    }
 
 
    mDrawingState.displays = mCurrentState.displays;
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::processDisplayRemoved(const wp<IBinder>& displayToken) {
    auto display = getDisplayDeviceLocked(displayToken);
    if (display) {
        display->disconnect();
 
 
        if (display->isVirtual()) {
            releaseVirtualDisplay(display->getVirtualId());
        } else {
            dispatchDisplayHotplugEvent(display->getPhysicalId(), false);
        }
    }
 
 
    mDisplays.erase(displayToken);
 
 
    if (display && display->isVirtual()) {
        static_cast<void>(mScheduler->schedule([display = std::move(display)] {
            // Destroy the display without holding the mStateLock.
            // This is a temporary solution until we can manage transaction queues without
            // holding the mStateLock.
            // With blast, the IGBP that is passed to the VirtualDisplaySurface is owned by the
            // client. When the IGBP is disconnected, its buffer cache in SF will be cleared
            // via SurfaceComposerClient::doUncacheBufferTransaction. This call from the client
            // ends up running on the main thread causing a deadlock since setTransactionstate
            // will try to acquire the mStateLock. Instead we extend the lifetime of
            // DisplayDevice and destroy it in the main thread without holding the mStateLock.
            // The display will be disconnected and removed from the mDisplays list so it will
            // not be accessible.
        }));
    }
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::processDisplayChanged(const wp<IBinder>& displayToken,
                                           const DisplayDeviceState& currentState,
                                           const DisplayDeviceState& drawingState) {
    const sp<IBinder> currentBinder = IInterface::asBinder(currentState.surface);
    const sp<IBinder> drawingBinder = IInterface::asBinder(drawingState.surface);
 
 
    // Recreate the DisplayDevice if the surface or sequence ID changed.
    if (currentBinder != drawingBinder || currentState.sequenceId != drawingState.sequenceId) {
        getRenderEngine().cleanFramebufferCache();
 
 
        if (const auto display = getDisplayDeviceLocked(displayToken)) {
            display->disconnect();
            if (display->isVirtual()) {
                releaseVirtualDisplay(display->getVirtualId());
            }
        }
 
 
        mDisplays.erase(displayToken);
 
 
        if (const auto& physical = currentState.physical) {
            getHwComposer().allocatePhysicalDisplay(physical->hwcDisplayId, physical->id);
        }
 
 
        processDisplayAdded(displayToken, currentState);
 
 
        if (currentState.physical) {
            const auto display = getDisplayDeviceLocked(displayToken);
            setPowerModeInternal(display, hal::PowerMode::ON);
 
 
            // TODO(b/175678251) Call a listener instead.
            if (currentState.physical->hwcDisplayId == getHwComposer().getPrimaryHwcDisplayId()) {
                updateInternalDisplayVsyncLocked(display);
            }
        }
        return;
    }
 
 
    if (const auto display = getDisplayDeviceLocked(displayToken)) {
        if (currentState.layerStack != drawingState.layerStack) {
            display->setLayerStack(currentState.layerStack);
        }
        if (currentState.flags != drawingState.flags) {
            display->setFlags(currentState.flags);
        }
        if ((currentState.orientation != drawingState.orientation) ||
            (currentState.layerStackSpaceRect != drawingState.layerStackSpaceRect) ||
            (currentState.orientedDisplaySpaceRect != drawingState.orientedDisplaySpaceRect)) {
            display->setProjection(currentState.orientation, currentState.layerStackSpaceRect,
                                   currentState.orientedDisplaySpaceRect);
            if (isDisplayActiveLocked(display)) {
                mActiveDisplayTransformHint = display->getTransformHint();
            }
        }
        if (currentState.width != drawingState.width ||
            currentState.height != drawingState.height) {
            display->setDisplaySize(currentState.width, currentState.height);
 
 
            if (isDisplayActiveLocked(display)) {
                onActiveDisplaySizeChanged(display);
            }
        }
    }
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::processDisplayAdded(const wp<IBinder>& displayToken,
                                         const DisplayDeviceState& state) {
    ui::Size resolution(0, 0);
    ui::PixelFormat pixelFormat = static_cast<ui::PixelFormat>(PIXEL_FORMAT_UNKNOWN);
    if (state.physical) {
        resolution = state.physical->activeMode->getResolution();
        pixelFormat = static_cast<ui::PixelFormat>(PIXEL_FORMAT_RGBA_8888);
    } else if (state.surface != nullptr) {
        int status = state.surface->query(NATIVE_WINDOW_WIDTH, &resolution.width);
        ALOGE_IF(status != NO_ERROR, "Unable to query width (%d)", status);
        status = state.surface->query(NATIVE_WINDOW_HEIGHT, &resolution.height);
        ALOGE_IF(status != NO_ERROR, "Unable to query height (%d)", status);
        int format;
        status = state.surface->query(NATIVE_WINDOW_FORMAT, &format);
        ALOGE_IF(status != NO_ERROR, "Unable to query format (%d)", status);
        pixelFormat = static_cast<ui::PixelFormat>(format);
    } else {
        // Virtual displays without a surface are dormant:
        // they have external state (layer stack, projection,
        // etc.) but no internal state (i.e. a DisplayDevice).
        return;
    }
 
 
    compositionengine::DisplayCreationArgsBuilder builder;
    if (const auto& physical = state.physical) {
        builder.setId(physical->id);
    } else {
        builder.setId(acquireVirtualDisplay(resolution, pixelFormat));
    }
 
 
    builder.setPixels(resolution);
    builder.setIsSecure(state.isSecure);
    builder.setPowerAdvisor(mPowerAdvisor.get());
    builder.setName(state.displayName);
    auto compositionDisplay = getCompositionEngine().createDisplay(builder.build());
    compositionDisplay->setLayerCachingEnabled(mLayerCachingEnabled);
 
 
    sp<compositionengine::DisplaySurface> displaySurface;
    sp<IGraphicBufferProducer> producer;
    sp<IGraphicBufferProducer> bqProducer;
    sp<IGraphicBufferConsumer> bqConsumer;
    getFactory().createBufferQueue(&bqProducer, &bqConsumer, /*consumerIsSurfaceFlinger =*/false);
 
 
    if (state.isVirtual()) {
        const auto displayId = VirtualDisplayId::tryCast(compositionDisplay->getId());
        LOG_FATAL_IF(!displayId);
        auto surface = sp<VirtualDisplaySurface>::make(getHwComposer(), *displayId, state.surface,
                                                       bqProducer, bqConsumer, state.displayName);
        displaySurface = surface;
        producer = std::move(surface);
    } else {
        ALOGE_IF(state.surface != nullptr,
                 "adding a supported display, but rendering "
                 "surface is provided (%p), ignoring it",
                 state.surface.get());
        const auto displayId = PhysicalDisplayId::tryCast(compositionDisplay->getId());
        LOG_FATAL_IF(!displayId);
        displaySurface =
                sp<FramebufferSurface>::make(getHwComposer(), *displayId, bqConsumer,
                                             state.physical->activeMode->getResolution(),
                                             ui::Size(maxGraphicsWidth, maxGraphicsHeight));
        producer = bqProducer;
    }
 
 
    LOG_FATAL_IF(!displaySurface);
    auto display = setupNewDisplayDeviceInternal(displayToken, std::move(compositionDisplay), state,
                                                 displaySurface, producer);
    if (display->isPrimary()) {
        initScheduler(display);
    }
    if (!state.isVirtual()) {
        dispatchDisplayHotplugEvent(display->getPhysicalId(), true);
    }
 
 
    mDisplays.try_emplace(displayToken, std::move(display));
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
std::unique_ptr<scheduler::Scheduler> mScheduler;
void SurfaceFlinger::initScheduler(const sp<DisplayDevice>& display) {
    if (mScheduler) {
        // If the scheduler is already initialized, this means that we received
        // a hotplug(connected) on the primary display. In that case we should
        // update the scheduler with the most recent display information.
        ALOGW("Scheduler already initialized, updating instead");
        mScheduler->setRefreshRateConfigs(display->holdRefreshRateConfigs());
        return;
    }
    const auto currRefreshRate = display->getActiveMode()->getFps();
    mRefreshRateStats = std::make_unique<scheduler::RefreshRateStats>(*mTimeStats, currRefreshRate,
                                                                      hal::PowerMode::OFF);
 
 
    mVsyncConfiguration = getFactory().createVsyncConfiguration(currRefreshRate);
    mVsyncModulator = sp<VsyncModulator>::make(mVsyncConfiguration->getCurrentConfigs());
 
 
    using Feature = scheduler::Feature;
    scheduler::FeatureFlags features;
 
 
    if (sysprop::use_content_detection_for_refresh_rate(false)) {
        features |= Feature::kContentDetection;
    }
    if (base::GetBoolProperty("debug.sf.show_predicted_vsync"s, false)) {
        features |= Feature::kTracePredictedVsync;
    }
    if (!base::GetBoolProperty("debug.sf.vsync_reactor_ignore_present_fences"s, false) &&
        !getHwComposer().hasCapability(Capability::PRESENT_FENCE_IS_NOT_RELIABLE)) {
        features |= Feature::kPresentFences;
    }
 
 
    // 创建Scheduler对象
    mScheduler = std::make_unique<scheduler::Scheduler>(static_cast<ICompositor&>(*this),
                                                        static_cast<ISchedulerCallback&>(*this),
                                                        features);
    {
        auto configs = display->holdRefreshRateConfigs();
        if (configs->kernelIdleTimerController().has_value()) {
            features |= Feature::kKernelIdleTimer;
        }
 
 
        mScheduler->createVsyncSchedule(features);
        mScheduler->setRefreshRateConfigs(std::move(configs));
    }
    setVsyncEnabled(false);
    mScheduler->startTimers();
 
 
    const auto configs = mVsyncConfiguration->getCurrentConfigs();
    const nsecs_t vsyncPeriod = currRefreshRate.getPeriodNsecs();
    mAppConnectionHandle =
            mScheduler->createConnection("app", mFrameTimeline->getTokenManager(),
                                         /*workDuration=*/configs.late.appWorkDuration,
                                         /*readyDuration=*/configs.late.sfWorkDuration,
                                         impl::EventThread::InterceptVSyncsCallback());
    mSfConnectionHandle =
            mScheduler->createConnection("appSf", mFrameTimeline->getTokenManager(),
                                         /*workDuration=*/std::chrono::nanoseconds(vsyncPeriod),
                                         /*readyDuration=*/configs.late.sfWorkDuration,
                                         [this](nsecs_t timestamp) {
                                             mInterceptor->saveVSyncEvent(timestamp);
                                         });
 
 
    mScheduler->initVsync(mScheduler->getVsyncDispatch(), *mFrameTimeline->getTokenManager(),
                          configs.late.sfWorkDuration);
 
 
    mRegionSamplingThread =
            new RegionSamplingThread(*this, RegionSamplingThread::EnvironmentTimingTunables());
    mFpsReporter = new FpsReporter(*mFrameTimeline, *this);
    // Dispatch a mode change request for the primary display on scheduler
    // initialization, so that the EventThreads always contain a reference to a
    // prior configuration.
    //
    // This is a bit hacky, but this avoids a back-pointer into the main SF
    // classes from EventThread, and there should be no run-time binder cost
    // anyway since there are no connected apps at this point.
    mScheduler->onPrimaryDisplayModeChanged(mAppConnectionHandle, display->getActiveMode());
}

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//frameworks/native/services/surfaceflinger/Scheduler/Scheduler.cpp
class Scheduler : impl::MessageQueue {
Scheduler::Scheduler(ICompositor& compositor, ISchedulerCallback& callback, FeatureFlags features)
      : impl::MessageQueue(compositor), mFeatures(features), mSchedulerCallback(callback) {}
}

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//frameworks/native/services/surfaceflinger/Scheduler/Scheduler.cpp
ConnectionHandle Scheduler::createConnection(
        const char* connectionName, frametimeline::TokenManager* tokenManager,
        std::chrono::nanoseconds workDuration, std::chrono::nanoseconds readyDuration,
        impl::EventThread::InterceptVSyncsCallback interceptCallback) {
    auto vsyncSource = makePrimaryDispSyncSource(connectionName, workDuration, readyDuration);
    auto throttleVsync = makeThrottleVsyncCallback();
    auto getVsyncPeriod = makeGetVsyncPeriodFunction();
    auto eventThread = std::make_unique<impl::EventThread>(std::move(vsyncSource), tokenManager,
                                                           std::move(interceptCallback),
                                                           std::move(throttleVsync),
                                                           std::move(getVsyncPeriod));
    return createConnection(std::move(eventThread));
}

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//frameworks/native/services/surfaceflinger/Scheduler/EventThread.cpp
class EventThread : public android::EventThread, private VSyncSource::Callback {
EventThread::EventThread(std::unique_ptr<VSyncSource> vsyncSource,
                         android::frametimeline::TokenManager* tokenManager,
                         InterceptVSyncsCallback interceptVSyncsCallback,
                         ThrottleVsyncCallback throttleVsyncCallback,
                         GetVsyncPeriodFunction getVsyncPeriodFunction)
      : mVSyncSource(std::move(vsyncSource)),
        mTokenManager(tokenManager),
        mInterceptVSyncsCallback(std::move(interceptVSyncsCallback)),
        mThrottleVsyncCallback(std::move(throttleVsyncCallback)),
        mGetVsyncPeriodFunction(std::move(getVsyncPeriodFunction)),
        mThreadName(mVSyncSource->getName()) {
 
 
    LOG_ALWAYS_FATAL_IF(getVsyncPeriodFunction == nullptr,
            "getVsyncPeriodFunction must not be null");
 
 
    mVSyncSource->setCallback(this); //设置VsyncSource回调
 
 
    mThread = std::thread([this]() NO_THREAD_SAFETY_ANALYSIS {
        std::unique_lock<std::mutex> lock(mMutex); //创建一个线程
        threadMain(lock); //调用threadMain方法，接收回调消息
    });
 
 
    pthread_setname_np(mThread.native_handle(), mThreadName);
 
 
    pid_t tid = pthread_gettid_np(mThread.native_handle());
 
 
    // Use SCHED_FIFO to minimize jitter
    constexpr int EVENT_THREAD_PRIORITY = 2;
    struct sched_param param = {0};
    param.sched_priority = EVENT_THREAD_PRIORITY;
    if (pthread_setschedparam(mThread.native_handle(), SCHED_FIFO, &param) != 0) {
        ALOGE("Couldn't set SCHED_FIFO for EventThread");
    }
 
 
    set_sched_policy(tid, SP_FOREGROUND);
}
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
InjectVSyncSource* mVSyncInjector = nullptr;
bool Scheduler::injectVSync(nsecs_t when, nsecs_t expectedVSyncTime, nsecs_t deadlineTimestamp) {
    if (!mInjectVSyncs || !mVSyncInjector) {
        return false;
    }
 
 
    mVSyncInjector->onInjectSyncEvent(when, expectedVSyncTime, deadlineTimestamp);
    return true;
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
class InjectVSyncSource final : public VSyncSource {
    void onInjectSyncEvent(nsecs_t when, nsecs_t expectedVSyncTimestamp,
                           nsecs_t deadlineTimestamp) {
        std::lock_guard<std::mutex> lock(mCallbackMutex);
        if (mCallback) {
            mCallback->onVSyncEvent(when, {expectedVSyncTimestamp, deadlineTimestamp});
        }
    }
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
std::unique_ptr<scheduler::Scheduler> mScheduler;
void SurfaceFlinger::run() {
    mScheduler->run();
}

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//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void Scheduler::run() {
    while (true) {
        waitMessage(); //等待消息
    }
}