设置->开发者选项->显示刷新频率
packages/apps/Settings/src/com/android/settings/development/ShowRefreshRatePreferenceController.java
public class ShowRefreshRatePreferenceController extends DeveloperOptionsPreferenceControllerimplements Preference.OnPreferenceChangeListener, PreferenceControllerMixin {......private static final int SETTING_VALUE_QUERY = 2;private static final int SETTING_VALUE_ON = 1;private static final int SETTING_VALUE_OFF = 0;@VisibleForTestingstatic final String SURFACE_FLINGER_SERVICE_KEY = "SurfaceFlinger";@VisibleForTestingstatic final int SURFACE_FLINGER_CODE = 1034;private static final String SURFACE_COMPOSER_INTERFACE_KEY = "android.ui.ISurfaceComposer";private final IBinder mSurfaceFlinger;......@Overridepublic boolean onPreferenceChange(Preference preference, Object newValue) {final boolean isEnabled = (Boolean) newValue;writeShowRefreshRateSetting(isEnabled);return true;}@Overridepublic void updateState(Preference preference) {updateShowRefreshRateSetting();}......@VisibleForTestingvoid updateShowRefreshRateSetting() {// magic communication with surface flinger.try {if (mSurfaceFlinger != null) {final Parcel data = Parcel.obtain();final Parcel reply = Parcel.obtain();data.writeInterfaceToken(SURFACE_COMPOSER_INTERFACE_KEY);data.writeInt(SETTING_VALUE_QUERY);mSurfaceFlinger.transact(SURFACE_FLINGER_CODE, data, reply, 0 /* flags */); // 调用 SurfaceFlinger::onTransact 中 1034 方法final boolean enabled = reply.readBoolean(); // 通过 SurfaceFlinger 获取 mRefreshRateOverlay != null判断显示是否打开((SwitchPreference) mPreference).setChecked(enabled);reply.recycle();data.recycle();}} catch (RemoteException ex) {// intentional no-op}}@VisibleForTestingvoid writeShowRefreshRateSetting(boolean isEnabled) { // 设置打开显示刷新频率try {if (mSurfaceFlinger != null) {final Parcel data = Parcel.obtain();data.writeInterfaceToken(SURFACE_COMPOSER_INTERFACE_KEY);final int showRefreshRate = isEnabled ? SETTING_VALUE_ON : SETTING_VALUE_OFF;data.writeInt(showRefreshRate);mSurfaceFlinger.transact(SURFACE_FLINGER_CODE, data,null /* reply */, 0 /* flags */);data.recycle();}} catch (RemoteException ex) {// intentional no-op}updateShowRefreshRateSetting();}
}
RefreshRateOverlay实际Layer显示刷新频率
frameworks\native\services\surfaceflinger\SurfaceFlinger.cpp
namespace {......
status_t SurfaceFlinger::onTransact(uint32_t code, const Parcel& data, Parcel* reply,uint32_t flags) {if (const status_t error = CheckTransactCodeCredentials(code); error != OK) {return error;}status_t err = BnSurfaceComposer::onTransact(code, data, reply, flags);if (err == UNKNOWN_TRANSACTION || err == PERMISSION_DENIED) {CHECK_INTERFACE(ISurfaceComposer, data, reply);IPCThreadState* ipc = IPCThreadState::self();const int uid = ipc->getCallingUid();if(code == 8002) {reply->writeInt32(mScheduler->getDfrcFps());return NO_ERROR;}if (CC_UNLIKELY(uid != AID_SYSTEM&& !PermissionCache::checkCallingPermission(sHardwareTest))) {const int pid = ipc->getCallingPid();ALOGE("Permission Denial: ""can't access SurfaceFlinger pid=%d, uid=%d", pid, uid);return PERMISSION_DENIED;}int n;switch (code) {......case 1034: {auto future = mScheduler->schedule([&] {switch (n = data.readInt32()) {case 0:case 1:FTL_FAKE_GUARD(mStateLock,enableRefreshRateOverlay(static_cast<bool>(n)));break;default: {reply->writeBool(FTL_FAKE_GUARD(mStateLock, isRefreshRateOverlayEnabled()));}}});future.wait();return NO_ERROR;}......
void SurfaceFlinger::enableRefreshRateOverlay(bool enable)
{for (const auto& [ignored, display] : mDisplays) {if (display->isInternal() && !display->isVirtual()) {if (enable) {auto fpsRange = display->refreshRateConfigs().getSupportedRefreshRateRange();mRefreshRateOverlay = std::make_shared<RefreshRateOverlay>(fpsRange, mRefreshRateOverlaySpinner);} else {mRefreshRateOverlay.reset(); //disable RefreshRateOverlay}display->enableRefreshRateOverlay(mRefreshRateOverlay);}}
}......
初始化RefreshRateOverlay
frameworks\native\services\surfaceflinger\RefreshRateOverlay.cpp
RefreshRateOverlay::RefreshRateOverlay(FpsRange fpsRange, bool showSpinner): mFpsRange(fpsRange),mShowSpinner(showSpinner),mSurfaceControl(SurfaceComposerClient::getDefault()->createSurface(String8("RefreshRateOverlay"), kBufferWidth,kBufferHeight, PIXEL_FORMAT_RGBA_8888,ISurfaceComposerClient::eFXSurfaceBufferState)) {if (!mSurfaceControl) {ALOGE("%s: Failed to create buffer state layer", __func__);return;}createTransaction(mSurfaceControl).setLayer(mSurfaceControl, INT32_MAX - 2).setTrustedOverlay(mSurfaceControl, true).apply();
}
