SurfaceFlinger的commit方法用于将应用程序的绘制结果提交到屏幕上显示。
主要就是处理app端发起的一系列transaction的事务请求，需要对这些请求进行识别是否当前帧处理，处理过程就是把事务中的属性取出，然后更新到Layer中，偶尔buffer更新的还需要进行相关的latchbuffer操作，SurfaceFlinger的commit代码如下：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
bool SurfaceFlinger::commit(nsecs_t frameTime, int64_t vsyncId, nsecs_t expectedVsyncTime) //这里frameTime代表当前时间，expectedVsyncTime代表硬件vsync时间，即屏幕先的vsync时间
FTL_FAKE_GUARD(kMainThreadContext) {
// we set this once at the beginning of commit to ensure consistency throughout the whole frame
mPowerHintSessionData.sessionEnabled = mPowerAdvisor->usePowerHintSession();
if (mPowerHintSessionData.sessionEnabled) {
mPowerHintSessionData.commitStart = systemTime();
}
// calculate the expected present time once and use the cached
// value throughout this frame to make sure all layers are
// seeing this same value.
if (expectedVsyncTime >= frameTime) {
mExpectedPresentTime = expectedVsyncTime;
} else {
const DisplayStatInfo stats = mScheduler->getDisplayStatInfo(frameTime);
mExpectedPresentTime = calculateExpectedPresentTime(stats);
}
const nsecs_t lastScheduledPresentTime = mScheduledPresentTime;
mScheduledPresentTime = expectedVsyncTime;
if (mPowerHintSessionData.sessionEnabled) {
mPowerAdvisor->setTargetWorkDuration(mExpectedPresentTime -
mPowerHintSessionData.commitStart);
}
const auto vsyncIn = [&] {
if (!ATRACE_ENABLED()) return 0.f;
return (mExpectedPresentTime - systemTime()) / 1e6f;
}();
ATRACE_FORMAT("%s %" PRId64 " vsyncIn %.2fms%s", __func__, vsyncId, vsyncIn,
mExpectedPresentTime == expectedVsyncTime ? "" : " (adjusted)");
// When Backpressure propagation is enabled we want to give a small grace period
// for the present fence to fire instead of just giving up on this frame to handle cases
// where present fence is just about to get signaled.
const int graceTimeForPresentFenceMs =
(mPropagateBackpressureClientComposition || !mHadClientComposition) ? 1 : 0;
// Pending frames may trigger backpressure propagation.
const TracedOrdinal<bool> framePending = {"PrevFramePending",
previousFramePending(graceTimeForPresentFenceMs)};
// Frame missed counts for metrics tracking.
// A frame is missed if the prior frame is still pending. If no longer pending,
// then we still count the frame as missed if the predicted present time
// was further in the past than when the fence actually fired.
// Add some slop to correct for drift. This should generally be
// smaller than a typical frame duration, but should not be so small
// that it reports reasonable drift as a missed frame.
const DisplayStatInfo stats = mScheduler->getDisplayStatInfo(systemTime());
const nsecs_t frameMissedSlop = stats.vsyncPeriod / 2;
const nsecs_t previousPresentTime = previousFramePresentTime();
const TracedOrdinal<bool> frameMissed = {"PrevFrameMissed",
framePending ||
(previousPresentTime >= 0 &&
(lastScheduledPresentTime <
previousPresentTime - frameMissedSlop))};
const TracedOrdinal<bool> hwcFrameMissed = {"PrevHwcFrameMissed",
mHadDeviceComposition && frameMissed};
const TracedOrdinal<bool> gpuFrameMissed = {"PrevGpuFrameMissed",
mHadClientComposition && frameMissed};
if (frameMissed) {
mFrameMissedCount++;
mTimeStats->incrementMissedFrames();
}
if (hwcFrameMissed) {
mHwcFrameMissedCount++;
}
if (gpuFrameMissed) {
mGpuFrameMissedCount++;
}
// If we are in the middle of a mode change and the fence hasn't
// fired yet just wait for the next commit.
// 如果我们正处于模式更改的过程中，并且围栏尚未触发，请等待下一次提交。
if (mSetActiveModePending) {
if (framePending) {
mScheduler->scheduleFrame();
return false;
}
// We received the present fence from the HWC, so we assume it successfully updated
// the mode, hence we update SF.
mSetActiveModePending = false;
{
Mutex::Autolock lock(mStateLock);
updateInternalStateWithChangedMode();
}
}
if (framePending) {
if ((hwcFrameMissed && !gpuFrameMissed) || mPropagateBackpressureClientComposition) {
scheduleCommit(FrameHint::kNone);
return false;
}
}
if (mTracingEnabledChanged) {
mLayerTracingEnabled = mLayerTracing.isEnabled();
mTracingEnabledChanged = false;
}
if (mRefreshRateOverlaySpinner) {
Mutex::Autolock lock(mStateLock);
if (const auto display = getDefaultDisplayDeviceLocked()) {
display->animateRefreshRateOverlay();
}
}
// Composite if transactions were committed, or if requested by HWC.
bool mustComposite = mMustComposite.exchange(false);
{
mFrameTimeline->setSfWakeUp(vsyncId, frameTime, Fps::fromPeriodNsecs(stats.vsyncPeriod));
bool needsTraversal = false;
if (clearTransactionFlags(eTransactionFlushNeeded)) { //满足eTransactionFlushNeeded条件进入
needsTraversal |= commitCreatedLayers(); //负责新创建的layer相关业务处理
needsTraversal |= flushTransactionQueues(vsyncId); //这里是对前面的Transaction处理的核心部分
}
const bool shouldCommit =
(getTransactionFlags() & ~eTransactionFlushNeeded) || needsTraversal;
if (shouldCommit) {
commitTransactions(); //进行Transaction提交主要就是交换mCurrentState和DrawingState
}
if (transactionFlushNeeded()) { //判断是否又要启动新vsync信号
setTransactionFlags(eTransactionFlushNeeded);
}
mustComposite |= shouldCommit;
mustComposite |= latchBuffers(); //进行核心的latchBuffer
// This has to be called after latchBuffers because we want to include the layers that have
// been latched in the commit callback
if (!needsTraversal) {
// Invoke empty transaction callbacks early.
mTransactionCallbackInvoker.sendCallbacks(false /* onCommitOnly */);
} else {
// Invoke OnCommit callbacks.
mTransactionCallbackInvoker.sendCallbacks(true /* onCommitOnly */);
}
updateLayerGeometry(); //对要这次vsync显示刷新的layer进行脏区设置
}
// Layers need to get updated (in the previous line) before we can use them for
// choosing the refresh rate.
// Hold mStateLock as chooseRefreshRateForContent promotes wp<Layer> to sp<Layer>
// and may eventually call to ~Layer() if it holds the last reference
{
Mutex::Autolock _l(mStateLock);
mScheduler->chooseRefreshRateForContent();
setActiveModeInHwcIfNeeded();
}
updateCursorAsync(); //鼠标相关layer处理
updateInputFlinger(); //更新触摸input下的相关的window等，这里也非常关键哈，直接影响触摸是否到app
if (mLayerTracingEnabled && !mLayerTracing.flagIsSet(LayerTracing::TRACE_COMPOSITION)) {
// This will block and tracing should only be enabled for debugging.
mLayerTracing.notify(mVisibleRegionsDirty, frameTime);
}
persistDisplayBrightness(mustComposite);
return mustComposite && CC_LIKELY(mBootStage != BootStage::BOOTLOADER);
}
上面方法主要处理如下：
1、调用SurfaceFlinger的commitCreatedLayers，创建的layer。
2、调用SurfaceFlinger的flushTransactionQueues方法。
3、调用SurfaceFlinger的commitTransactions方法，进行Transaction提交。
4、调用SurfaceFlinger的latchBuffers方法，将应用程序的图形缓冲区（buffer）与显示器进行关联。
5、调用SurfaceFlinger的updateLayerGeometry方法，这次vsync显示刷新的layer进行脏区设置。
6、调用SurfaceFlinger的updateInputFlinger方法，更新输入处理。
下面分别进行分析：
SurfaceFlinger commitCreatedLayers
调用SurfaceFlinger的commitCreatedLayers，创建的layer：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
bool SurfaceFlinger::commitCreatedLayers() {
std::vector<LayerCreatedState> createdLayers;
{
std::scoped_lock<std::mutex> lock(mCreatedLayersLock);
createdLayers = std::move(mCreatedLayers);
mCreatedLayers.clear();
if (createdLayers.size() == 0) {
return false;
}
}
Mutex::Autolock _l(mStateLock);
for (const auto& createdLayer : createdLayers) {
handleLayerCreatedLocked(createdLayer);
}
createdLayers.clear();
mLayersAdded = true;
return true;
}
SurfaceFlinger flushTransactionQueues
调用SurfaceFlinger的flushTransactionQueues方法：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
bool SurfaceFlinger::flushTransactionQueues(int64_t vsyncId) {
// to prevent onHandleDestroyed from being called while the lock is held,
// we must keep a copy of the transactions (specifically the composer
// states) around outside the scope of the lock
std::vector<TransactionState> transactions;
// Layer handles that have transactions with buffers that are ready to be applied.
std::unordered_map<sp<IBinder>, uint64_t, SpHash<IBinder>> bufferLayersReadyToPresent;
std::unordered_set<sp<IBinder>, SpHash<IBinder>> applyTokensWithUnsignaledTransactions;
{
Mutex::Autolock _l(mStateLock);
{
Mutex::Autolock _l(mQueueLock);
int lastTransactionsPendingBarrier = 0;
int transactionsPendingBarrier = 0;
// First collect transactions from the pending transaction queues.
// We are not allowing unsignaled buffers here as we want to
// collect all the transactions from applyTokens that are ready first.
//刷新一下PendingTransactionQueues，这个主要是上次vsync中没有满足条件的Transaction放入的
transactionsPendingBarrier =
flushPendingTransactionQueues(transactions, bufferLayersReadyToPresent,
applyTokensWithUnsignaledTransactions, /*tryApplyUnsignaled*/ false);
// Second, collect transactions from the transaction queue.
// Here as well we are not allowing unsignaled buffers for the same
// reason as above.
//开始遍历当次vsync的mTransactionQueue
while (!mTransactionQueue.empty()) {
auto& transaction = mTransactionQueue.front();
//判断是否处于mPendingTransactionQueues队里里面
const bool pendingTransactions =
mPendingTransactionQueues.find(transaction.applyToken) !=
mPendingTransactionQueues.end();
//这里有个ready的判断，主要就是看看当前的Transaction是否已经ready，没有ready则不予进行传递Transaction
const auto ready = [&]() REQUIRES(mStateLock) {
if (pendingTransactions) {
ATRACE_NAME("pendingTransactions");
return TransactionReadiness::NotReady;
}
return transactionIsReadyToBeApplied(transaction, transaction.frameTimelineInfo,
transaction.isAutoTimestamp,
transaction.desiredPresentTime,
transaction.originUid, transaction.states,
bufferLayersReadyToPresent,
transactions.size(),
/*tryApplyUnsignaled*/ false); //检查当前的事务是否准备好被应用
}();
ATRACE_INT("TransactionReadiness", static_cast<int>(ready));
if (ready != TransactionReadiness::Ready) {
if (ready == TransactionReadiness::NotReadyBarrier) {
transactionsPendingBarrier++;
}
//放入mPendingTransactionQueues
mPendingTransactionQueues[transaction.applyToken].push(std::move(transaction));
} else {
//已经ready则进入如下的操作
transaction.traverseStatesWithBuffers([&](const layer_state_t& state) {
const bool frameNumberChanged = state.bufferData->flags.test(
BufferData::BufferDataChange::frameNumberChanged);
//会把state放入到bufferLayersReadyToPresent这个map中
if (frameNumberChanged) {
bufferLayersReadyToPresent[state.surface] = state.bufferData->frameNumber;
} else {
// Barrier function only used for BBQ which always includes a frame number.
// This value only used for barrier logic.
bufferLayersReadyToPresent[state.surface] =
std::numeric_limits<uint64_t>::max();
}
});
//最重要的放入到transactions
transactions.emplace_back(std::move(transaction));
}
//从mTransactionQueue这里移除
mTransactionQueue.pop_front();
ATRACE_INT("TransactionQueue", mTransactionQueue.size());
}
// Transactions with a buffer pending on a barrier may be on a different applyToken
// than the transaction which satisfies our barrier. In fact this is the exact use case
// that the primitive is designed for. This means we may first process
// the barrier dependent transaction, determine it ineligible to complete
// and then satisfy in a later inner iteration of flushPendingTransactionQueues.
// The barrier dependent transaction was eligible to be presented in this frame
// but we would have prevented it without case. To fix this we continually
// loop through flushPendingTransactionQueues until we perform an iteration
// where the number of transactionsPendingBarrier doesn't change. This way
// we can continue to resolve dependency chains of barriers as far as possible.
while (lastTransactionsPendingBarrier != transactionsPendingBarrier) {
lastTransactionsPendingBarrier = transactionsPendingBarrier;
transactionsPendingBarrier =
flushPendingTransactionQueues(transactions, bufferLayersReadyToPresent,
applyTokensWithUnsignaledTransactions,
/*tryApplyUnsignaled*/ false);
}
// We collected all transactions that could apply without latching unsignaled buffers.
// If we are allowing latch unsignaled of some form, now it's the time to go over the
// transactions that were not applied and try to apply them unsignaled.
//根据enableLatchUnsignaledConfig属性，不是disabled的话需要对前面的notready情况进行第二次的校验放过
if (enableLatchUnsignaledConfig != LatchUnsignaledConfig::Disabled) {
flushUnsignaledPendingTransactionQueues(transactions, bufferLayersReadyToPresent,
applyTokensWithUnsignaledTransactions);
}
//进行关键的applyTransactions操作
return applyTransactions(transactions, vsyncId);
}
}
}
上面方法的主要处理如下：
1、调用SurfaceFlinger的transactionIsReadyToBeApplied方法，检查当前的事务是否准备好被应用
2、调用SurfaceFlinger的applyTransactions方法，应用事务。
下面分别进行分析：
SurfaceFlinger transactionIsReadyToBeApplied
调用SurfaceFlinger的transactionIsReadyToBeApplied方法，检查当前的事务是否准备好被应用：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
auto SurfaceFlinger::transactionIsReadyToBeApplied(TransactionState& transaction,
const FrameTimelineInfo& info, bool isAutoTimestamp, int64_t desiredPresentTime,
uid_t originUid, const Vector<ComposerState>& states,
const std::unordered_map<
sp<IBinder>, uint64_t, SpHash<IBinder>>& bufferLayersReadyToPresent,
size_t totalTXapplied, bool tryApplyUnsignaled) const -> TransactionReadiness {
ATRACE_FORMAT("transactionIsReadyToBeApplied vsyncId: %" PRId64, info.vsyncId);
const nsecs_t expectedPresentTime = mExpectedPresentTime.load();
// Do not present if the desiredPresentTime has not passed unless it is more than one second
// in the future. We ignore timestamps more than 1 second in the future for stability reasons.
if (!isAutoTimestamp && desiredPresentTime >= expectedPresentTime &&
desiredPresentTime < expectedPresentTime + s2ns(1)) {
ATRACE_NAME("not current");
return TransactionReadiness::NotReady;
}
if (!mScheduler->isVsyncValid(expectedPresentTime, originUid)) {
ATRACE_NAME("!isVsyncValid");
return TransactionReadiness::NotReady;
}
// If the client didn't specify desiredPresentTime, use the vsyncId to determine the expected
// present time of this transaction.
if (isAutoTimestamp && frameIsEarly(expectedPresentTime, info.vsyncId)) {
ATRACE_NAME("frameIsEarly");
return TransactionReadiness::NotReady;
}
bool fenceUnsignaled = false;
auto queueProcessTime = systemTime();
//关键部分对transaction的states进行挨个state遍历情况
for (const ComposerState& state : states) {
const layer_state_t& s = state.state;
sp<Layer> layer = nullptr;
//这里会判断到底有没有surface。没有的话就不会进入下面判断环节
if (s.surface) {
layer = fromHandle(s.surface).promote();
} else if (s.hasBufferChanges()) {
ALOGW("Transaction with buffer, but no Layer?");
continue;
}
if (!layer) {
continue;
}
if (s.hasBufferChanges() && s.bufferData->hasBarrier &&
((layer->getDrawingState().frameNumber) < s.bufferData->barrierFrameNumber)) {
const bool willApplyBarrierFrame =
(bufferLayersReadyToPresent.find(s.surface) != bufferLayersReadyToPresent.end()) &&
(bufferLayersReadyToPresent.at(s.surface) >= s.bufferData->barrierFrameNumber);
if (!willApplyBarrierFrame) {
ATRACE_NAME("NotReadyBarrier");
return TransactionReadiness::NotReadyBarrier;
}
}
//注意这里会有一个标志allowLatchUnsignaled意思是是否可以latch非signaled的buffer
const bool allowLatchUnsignaled = tryApplyUnsignaled &&
shouldLatchUnsignaled(layer, s, states.size(), totalTXapplied);
ATRACE_FORMAT("%s allowLatchUnsignaled=%s", layer->getName().c_str(),
allowLatchUnsignaled ? "true" : "false");
const bool acquireFenceChanged = s.bufferData &&
s.bufferData->flags.test(BufferData::BufferDataChange::fenceChanged) &&
s.bufferData->acquireFence;
//这里会进行关键的判断，判断state的bufferData->acquireFence是否已经signaled
fenceUnsignaled = fenceUnsignaled ||
(acquireFenceChanged &&
s.bufferData->acquireFence->getStatus() == Fence::Status::Unsignaled);
//如果fenceUnsignaled属于fenceUnsignaled，allowLatchUnsignaled也为false
if (fenceUnsignaled && !allowLatchUnsignaled) {
if (!transaction.sentFenceTimeoutWarning &&
queueProcessTime - transaction.queueTime > std::chrono::nanoseconds(4s).count()) {
transaction.sentFenceTimeoutWarning = true;
auto listener = s.bufferData->releaseBufferListener;
if (listener) {
listener->onTransactionQueueStalled();
}
}
//那么就代表不可以传递transaction，会返回NotReady
ATRACE_NAME("fence unsignaled");
return TransactionReadiness::NotReady;
}
if (s.hasBufferChanges()) {
// If backpressure is enabled and we already have a buffer to commit, keep the
// transaction in the queue.
const bool hasPendingBuffer = bufferLayersReadyToPresent.find(s.surface) !=
bufferLayersReadyToPresent.end();
//如果前面已经有state放入了，则不在放入，会放入pending
if (layer->backpressureEnabled() && hasPendingBuffer && isAutoTimestamp) {
ATRACE_NAME("hasPendingBuffer");
return TransactionReadiness::NotReady;
}
}
}
return fenceUnsignaled ? TransactionReadiness::ReadyUnsignaled : TransactionReadiness::Ready;
}
SurfaceFlinger applyTransactions
调用SurfaceFlinger的applyTransactions方法，应用事务：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
bool SurfaceFlinger::applyTransactions(std::vector<TransactionState>& transactions,
int64_t vsyncId) {
bool needsTraversal = false;
// Now apply all transactions.
//遍历每一个上面判断为ready的transaction
for (auto& transaction : transactions) {
//核心方法又调用到了applyTransactionState
needsTraversal |=
applyTransactionState(transaction.frameTimelineInfo, transaction.states,
transaction.displays, transaction.flags,
transaction.inputWindowCommands,
transaction.desiredPresentTime, transaction.isAutoTimestamp,
transaction.buffer, transaction.postTime,
transaction.permissions, transaction.hasListenerCallbacks,
transaction.listenerCallbacks, transaction.originPid,
transaction.originUid, transaction.id);
if (transaction.transactionCommittedSignal) {
mTransactionCommittedSignals.emplace_back(
std::move(transaction.transactionCommittedSignal));
}
}
if (mTransactionTracing) {
mTransactionTracing->addCommittedTransactions(transactions, vsyncId);
}
return needsTraversal;
}
SurfaceFlinger applyTransactionState
调用SurfaceFlinger的applyTransactionState方法：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
bool SurfaceFlinger::applyTransactionState(const FrameTimelineInfo& frameTimelineInfo,
Vector<ComposerState>& states,
const Vector<DisplayState>& displays, uint32_t flags,
const InputWindowCommands& inputWindowCommands,
const int64_t desiredPresentTime, bool isAutoTimestamp,
const client_cache_t& uncacheBuffer,
const int64_t postTime, uint32_t permissions,
bool hasListenerCallbacks,
const std::vector<ListenerCallbacks>& listenerCallbacks,
int originPid, int originUid, uint64_t transactionId) {
uint32_t transactionFlags = 0;
//遍历是transaction的dispplays
for (const DisplayState& display : displays) {
//遍历是否有dispplay相关的变化
transactionFlags |= setDisplayStateLocked(display);
}
// start and end registration for listeners w/ no surface so they can get their callback. Note
// that listeners with SurfaceControls will start registration during setClientStateLocked
// below.
for (const auto& listener : listenerCallbacks) {
mTransactionCallbackInvoker.addEmptyTransaction(listener);
}
uint32_t clientStateFlags = 0;
for (int i = 0; i < states.size(); i++) { //最关键方法开始遍历一个个的states
ComposerState& state = states.editItemAt(i);
//调用到了setClientStateLocked方法
clientStateFlags |= setClientStateLocked(frameTimelineInfo, state, desiredPresentTime,
isAutoTimestamp, postTime, permissions);
if ((flags & eAnimation) && state.state.surface) {
if (const auto layer = fromHandle(state.state.surface).promote()) {
using LayerUpdateType = scheduler::LayerHistory::LayerUpdateType;
mScheduler->recordLayerHistory(layer.get(),
isAutoTimestamp ? 0 : desiredPresentTime,
LayerUpdateType::AnimationTX);
}
}
}
transactionFlags |= clientStateFlags;
if (permissions & layer_state_t::Permission::ACCESS_SURFACE_FLINGER) {
transactionFlags |= addInputWindowCommands(inputWindowCommands);
} else if (!inputWindowCommands.empty()) {
ALOGE("Only privileged callers are allowed to send input commands.");
}
if (uncacheBuffer.isValid()) {
ClientCache::getInstance().erase(uncacheBuffer);
}
// If a synchronous transaction is explicitly requested without any changes, force a transaction
// anyway. This can be used as a flush mechanism for previous async transactions.
// Empty animation transaction can be used to simulate back-pressure, so also force a
// transaction for empty animation transactions.
if (transactionFlags == 0 &&
((flags & eSynchronous) || (flags & eAnimation))) {
transactionFlags = eTransactionNeeded;
}
bool needsTraversal = false;
if (transactionFlags) {
if (mInterceptor->isEnabled()) {
mInterceptor->saveTransaction(states, mCurrentState.displays, displays, flags,
originPid, originUid, transactionId);
}
// We are on the main thread, we are about to preform a traversal. Clear the traversal bit
// so we don't have to wake up again next frame to preform an unnecessary traversal.
if (transactionFlags & eTraversalNeeded) {
transactionFlags = transactionFlags & (~eTraversalNeeded);
needsTraversal = true;
}
if (transactionFlags) {
setTransactionFlags(transactionFlags);
}
if (flags & eAnimation) {
mAnimTransactionPending = true;
}
}
return needsTraversal;
}
SurfaceFlinger setClientStateLocked
调用SurfaceFlinger的setClientStateLocked方法：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
uint32_t SurfaceFlinger::setClientStateLocked(const FrameTimelineInfo& frameTimelineInfo,
ComposerState& composerState,
int64_t desiredPresentTime, bool isAutoTimestamp,
int64_t postTime, uint32_t permissions) {
layer_state_t& s = composerState.state;
s.sanitize(permissions);
std::vector<ListenerCallbacks> filteredListeners;
for (auto& listener : s.listeners) {
// Starts a registration but separates the callback ids according to callback type. This
// allows the callback invoker to send on latch callbacks earlier.
// note that startRegistration will not re-register if the listener has
// already be registered for a prior surface control
ListenerCallbacks onCommitCallbacks = listener.filter(CallbackId::Type::ON_COMMIT);
if (!onCommitCallbacks.callbackIds.empty()) {
filteredListeners.push_back(onCommitCallbacks);
}
ListenerCallbacks onCompleteCallbacks = listener.filter(CallbackId::Type::ON_COMPLETE);
if (!onCompleteCallbacks.callbackIds.empty()) {
filteredListeners.push_back(onCompleteCallbacks);
}
}
const uint64_t what = s.what;
uint32_t flags = 0;
sp<Layer> layer = nullptr;
if (s.surface) {
layer = fromHandle(s.surface).promote();
} else {
// The client may provide us a null handle. Treat it as if the layer was removed.
ALOGW("Attempt to set client state with a null layer handle");
}
if (layer == nullptr) {
for (auto& [listener, callbackIds] : s.listeners) {
mTransactionCallbackInvoker.registerUnpresentedCallbackHandle(
new CallbackHandle(listener, callbackIds, s.surface));
}
return 0;
}
// Only set by BLAST adapter layers
if (what & layer_state_t::eProducerDisconnect) {
layer->onDisconnect();
}
if (what & layer_state_t::ePositionChanged) {
if (layer->setPosition(s.x, s.y)) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eLayerChanged) {
// NOTE: index needs to be calculated before we update the state
const auto& p = layer->getParent();
if (p == nullptr) {
ssize_t idx = mCurrentState.layersSortedByZ.indexOf(layer);
if (layer->setLayer(s.z) && idx >= 0) {
mCurrentState.layersSortedByZ.removeAt(idx);
mCurrentState.layersSortedByZ.add(layer);
// we need traversal (state changed)
// AND transaction (list changed)
flags |= eTransactionNeeded|eTraversalNeeded;
}
} else {
if (p->setChildLayer(layer, s.z)) {
flags |= eTransactionNeeded|eTraversalNeeded;
}
}
}
if (what & layer_state_t::eRelativeLayerChanged) {
// NOTE: index needs to be calculated before we update the state
const auto& p = layer->getParent();
const auto& relativeHandle = s.relativeLayerSurfaceControl ?
s.relativeLayerSurfaceControl->getHandle() : nullptr;
if (p == nullptr) {
ssize_t idx = mCurrentState.layersSortedByZ.indexOf(layer);
if (layer->setRelativeLayer(relativeHandle, s.z) &&
idx >= 0) {
mCurrentState.layersSortedByZ.removeAt(idx);
mCurrentState.layersSortedByZ.add(layer);
// we need traversal (state changed)
// AND transaction (list changed)
flags |= eTransactionNeeded|eTraversalNeeded;
}
} else {
if (p->setChildRelativeLayer(layer, relativeHandle, s.z)) {
flags |= eTransactionNeeded|eTraversalNeeded;
}
}
}
if (what & layer_state_t::eSizeChanged) {
if (layer->setSize(s.w, s.h)) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eAlphaChanged) {
if (layer->setAlpha(s.alpha))
flags |= eTraversalNeeded;
}
if (what & layer_state_t::eColorChanged) {
if (layer->setColor(s.color))
flags |= eTraversalNeeded;
}
if (what & layer_state_t::eColorTransformChanged) {
if (layer->setColorTransform(s.colorTransform)) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eBackgroundColorChanged) {
if (layer->setBackgroundColor(s.color, s.bgColorAlpha, s.bgColorDataspace)) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eMatrixChanged) {
if (layer->setMatrix(s.matrix)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eTransparentRegionChanged) {
if (layer->setTransparentRegionHint(s.transparentRegion))
flags |= eTraversalNeeded;
}
if (what & layer_state_t::eFlagsChanged) {
if (layer->setFlags(s.flags, s.mask)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eCornerRadiusChanged) {
if (layer->setCornerRadius(s.cornerRadius))
flags |= eTraversalNeeded;
}
if (what & layer_state_t::eBackgroundBlurRadiusChanged && mSupportsBlur) {
if (layer->setBackgroundBlurRadius(s.backgroundBlurRadius)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eBlurRegionsChanged) {
if (layer->setBlurRegions(s.blurRegions)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eLayerStackChanged) {
ssize_t idx = mCurrentState.layersSortedByZ.indexOf(layer);
// We only allow setting layer stacks for top level layers,
// everything else inherits layer stack from its parent.
if (layer->hasParent()) {
ALOGE("Attempt to set layer stack on layer with parent (%s) is invalid",
layer->getDebugName());
} else if (idx < 0) {
ALOGE("Attempt to set layer stack on layer without parent (%s) that "
"that also does not appear in the top level layer list. Something"
" has gone wrong.",
layer->getDebugName());
} else if (layer->setLayerStack(s.layerStack)) {
mCurrentState.layersSortedByZ.removeAt(idx);
mCurrentState.layersSortedByZ.add(layer);
// we need traversal (state changed)
// AND transaction (list changed)
flags |= eTransactionNeeded | eTraversalNeeded | eTransformHintUpdateNeeded;
}
}
if (what & layer_state_t::eTransformChanged) {
if (layer->setTransform(s.transform)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eTransformToDisplayInverseChanged) {
if (layer->setTransformToDisplayInverse(s.transformToDisplayInverse))
flags |= eTraversalNeeded;
}
if (what & layer_state_t::eCropChanged) {
if (layer->setCrop(s.crop)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eDataspaceChanged) {
if (layer->setDataspace(s.dataspace)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eHdrMetadataChanged) {
if (layer->setHdrMetadata(s.hdrMetadata)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eSurfaceDamageRegionChanged) {
if (layer->setSurfaceDamageRegion(s.surfaceDamageRegion)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eApiChanged) {
if (layer->setApi(s.api)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eSidebandStreamChanged) {
if (layer->setSidebandStream(s.sidebandStream)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eInputInfoChanged) {
layer->setInputInfo(*s.windowInfoHandle->getInfo());
flags |= eTraversalNeeded;
}
std::optional<nsecs_t> dequeueBufferTimestamp;
if (what & layer_state_t::eMetadataChanged) {
dequeueBufferTimestamp = s.metadata.getInt64(METADATA_DEQUEUE_TIME);
if (const int32_t gameMode = s.metadata.getInt32(METADATA_GAME_MODE, -1); gameMode != -1) {
// The transaction will be received on the Task layer and needs to be applied to all
// child layers. Child layers that are added at a later point will obtain the game mode
// info through addChild().
layer->setGameModeForTree(static_cast<GameMode>(gameMode));
}
if (layer->setMetadata(s.metadata)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eColorSpaceAgnosticChanged) {
if (layer->setColorSpaceAgnostic(s.colorSpaceAgnostic)) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eShadowRadiusChanged) {
if (layer->setShadowRadius(s.shadowRadius)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eFrameRateSelectionPriority) {
if (layer->setFrameRateSelectionPriority(s.frameRateSelectionPriority)) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eFrameRateChanged) {
const auto compatibility =
Layer::FrameRate::convertCompatibility(s.frameRateCompatibility);
const auto strategy =
Layer::FrameRate::convertChangeFrameRateStrategy(s.changeFrameRateStrategy);
if (layer->setFrameRate(
Layer::FrameRate(Fps::fromValue(s.frameRate), compatibility, strategy))) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eFixedTransformHintChanged) {
if (layer->setFixedTransformHint(s.fixedTransformHint)) {
flags |= eTraversalNeeded | eTransformHintUpdateNeeded;
}
}
if (what & layer_state_t::eAutoRefreshChanged) {
layer->setAutoRefresh(s.autoRefresh);
}
if (what & layer_state_t::eDimmingEnabledChanged) {
if (layer->setDimmingEnabled(s.dimmingEnabled)) flags |= eTraversalNeeded;
}
if (what & layer_state_t::eTrustedOverlayChanged) {
if (layer->setTrustedOverlay(s.isTrustedOverlay)) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eStretchChanged) {
if (layer->setStretchEffect(s.stretchEffect)) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eBufferCropChanged) {
if (layer->setBufferCrop(s.bufferCrop)) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eDestinationFrameChanged) {
if (layer->setDestinationFrame(s.destinationFrame)) {
flags |= eTraversalNeeded;
}
}
if (what & layer_state_t::eDropInputModeChanged) {
if (layer->setDropInputMode(s.dropInputMode)) {
flags |= eTraversalNeeded;
mInputInfoChanged = true;
}
}
// This has to happen after we reparent children because when we reparent to null we remove
// child layers from current state and remove its relative z. If the children are reparented in
// the same transaction, then we have to make sure we reparent the children first so we do not
// lose its relative z order.
if (what & layer_state_t::eReparent) {
bool hadParent = layer->hasParent();
auto parentHandle = (s.parentSurfaceControlForChild)
? s.parentSurfaceControlForChild->getHandle()
: nullptr;
if (layer->reparent(parentHandle)) {
if (!hadParent) {
layer->setIsAtRoot(false);
mCurrentState.layersSortedByZ.remove(layer);
}
flags |= eTransactionNeeded | eTraversalNeeded;
}
}
std::vector<sp<CallbackHandle>> callbackHandles;
if ((what & layer_state_t::eHasListenerCallbacksChanged) && (!filteredListeners.empty())) {
for (auto& [listener, callbackIds] : filteredListeners) {
callbackHandles.emplace_back(new CallbackHandle(listener, callbackIds, s.surface));
}
}
if (what & layer_state_t::eBufferChanged) { //如果发现有buffer变化
std::shared_ptr<renderengine::ExternalTexture> buffer =
getExternalTextureFromBufferData(*s.bufferData, layer->getDebugName());
//把state的bufferData相关信息设置到了layer中去
if (layer->setBuffer(buffer, *s.bufferData, postTime, desiredPresentTime, isAutoTimestamp,
dequeueBufferTimestamp, frameTimelineInfo)) {
flags |= eTraversalNeeded;
}
} else if (frameTimelineInfo.vsyncId != FrameTimelineInfo::INVALID_VSYNC_ID) {
layer->setFrameTimelineVsyncForBufferlessTransaction(frameTimelineInfo, postTime);
}
if (layer->setTransactionCompletedListeners(callbackHandles)) flags |= eTraversalNeeded;
// Do not put anything that updates layer state or modifies flags after
// setTransactionCompletedListener
return flags;
}
SurfaceFlinger commitTransactions
调用SurfaceFlinger的commitTransactions方法，进行Transaction提交：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::commitTransactions() {
ATRACE_CALL();
// Keep a copy of the drawing state (that is going to be overwritten
// by commitTransactionsLocked) outside of mStateLock so that the side
// effects of the State assignment don't happen with mStateLock held,
// which can cause deadlocks.
State drawingState(mDrawingState);
Mutex::Autolock lock(mStateLock);
mDebugInTransaction = systemTime();
// Here we're guaranteed that some transaction flags are set
// so we can call commitTransactionsLocked unconditionally.
// We clear the flags with mStateLock held to guarantee that
// mCurrentState won't change until the transaction is committed.
modulateVsync(&VsyncModulator::onTransactionCommit);
commitTransactionsLocked(clearTransactionFlags(eTransactionMask));
mDebugInTransaction = 0;
}
调用SurfaceFlinger的commitTransactionsLocked方法：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::commitTransactionsLocked(uint32_t transactionFlags) {
// Commit display transactions.
const bool displayTransactionNeeded = transactionFlags & eDisplayTransactionNeeded;
if (displayTransactionNeeded) { //如果需要显示
processDisplayChangesLocked(); //处理显示变化相关
processDisplayHotplugEventsLocked();
}
mForceTransactionDisplayChange = displayTransactionNeeded;
if (mSomeChildrenChanged) {
mVisibleRegionsDirty = true;
mSomeChildrenChanged = false;
}
// Update transform hint.
if (transactionFlags & (eTransformHintUpdateNeeded | eDisplayTransactionNeeded)) {
// Layers and/or displays have changed, so update the transform hint for each layer.
//
// NOTE: we do this here, rather than when presenting the display so that
// the hint is set before we acquire a buffer from the surface texture.
//
// NOTE: layer transactions have taken place already, so we use their
// drawing state. However, SurfaceFlinger's own transaction has not
// happened yet, so we must use the current state layer list
// (soon to become the drawing state list).
//
sp<const DisplayDevice> hintDisplay;
ui::LayerStack layerStack;
mCurrentState.traverse([&](Layer* layer) REQUIRES(mStateLock) {
// NOTE: we rely on the fact that layers are sorted by
// layerStack first (so we don't have to traverse the list
// of displays for every layer).
if (const auto filter = layer->getOutputFilter(); layerStack != filter.layerStack) {
layerStack = filter.layerStack;
hintDisplay = nullptr;
// Find the display that includes the layer.
for (const auto& [token, display] : mDisplays) {
if (!display->getCompositionDisplay()->includesLayer(filter)) {
continue;
}
// Pick the primary display if another display mirrors the layer.
if (hintDisplay) {
hintDisplay = nullptr;
break;
}
hintDisplay = display;
}
}
if (!hintDisplay) {
// NOTE: TEMPORARY FIX ONLY. Real fix should cause layers to
// redraw after transform hint changes. See bug 8508397.
// could be null when this layer is using a layerStack
// that is not visible on any display. Also can occur at
// screen off/on times.
hintDisplay = getDefaultDisplayDeviceLocked();
}
layer->updateTransformHint(hintDisplay->getTransformHint());
});
}
if (mLayersAdded) {
mLayersAdded = false;
// Layers have been added.
mVisibleRegionsDirty = true;
}
// some layers might have been removed, so
// we need to update the regions they're exposing.
if (mLayersRemoved) {
mLayersRemoved = false;
mVisibleRegionsDirty = true;
mDrawingState.traverseInZOrder([&](Layer* layer) {
if (mLayersPendingRemoval.indexOf(layer) >= 0) {
// this layer is not visible anymore
Region visibleReg;
visibleReg.set(layer->getScreenBounds());
invalidateLayerStack(layer, visibleReg);
}
});
}
doCommitTransactions();
signalSynchronousTransactions(CountDownLatch::eSyncTransaction);
mAnimTransactionPending = false;
}
上面方法主要处理如下：
1、调用SurfaceFlinger的processDisplayChangesLocked方法，处理显示器变化相关。
2、调用SurfaceFlinger的doCommitTransactions方法，执行提交事务。
下面分别进行分析：
SurfaceFlinger processDisplayChangesLocked
调用SurfaceFlinger的processDisplayChangesLocked方法：
//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
// 处于绘图状态，但不在当前状态
processDisplayRemoved(displayToken);
} else {
// this display is in both lists. see if something changed.
// 此显示在两个列表中。看看是否有变化。
const DisplayDeviceState& currentState = curr[j];
const DisplayDeviceState& drawingState = draw[i];
processDisplayChanged(displayToken, currentState, drawingState);
}
}
// find displays that were added
// 查找已添加的显示
// (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;
}
上面方法根据不同的调节调用如下方法：
1、调用processDisplayRemoved方法，处理显示器删除。
2、调用processDisplayChanged方法，处理显示器变更。
3、调用processDisplayAdded方法，处理显示器添加。
下面分别进行分析：
SurfaceFlinger processDisplayRemoved
调用processDisplayRemoved方法，处理显示器删除：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::processDisplayRemoved(const wp<IBinder>& displayToken) {
auto display = getDisplayDeviceLocked(displayToken);
if (display) {
display->disconnect(); //与Display断开连接
if (display->isVirtual()) {
releaseVirtualDisplay(display->getVirtualId()); //如果是虚拟显示器，就进行资源释放
} else {
dispatchDisplayHotplugEvent(display->getPhysicalId(), false); //分配显示器热插拔事件
}
}
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.
}));
}
}
SurfaceFlinger processDisplayChanged
调用processDisplayChanged方法，处理显示器变更：
//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.
// 如果图面或序列 ID 发生更改，请重新创建 DisplayDevice。
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); //设置显示器层堆栈
}
if (currentState.flags != drawingState.flags) {
display->setFlags(currentState.flags); //设置显示器标志
}
if ((currentState.orientation != drawingState.orientation) ||
(currentState.layerStackSpaceRect != drawingState.layerStackSpaceRect) ||
(currentState.orientedDisplaySpaceRect != drawingState.orientedDisplaySpaceRect)) {
display->setProjection(currentState.orientation, currentState.layerStackSpaceRect,
currentState.orientedDisplaySpaceRect); //设置显示器投影
if (isDisplayActiveLocked(display)) {
mActiveDisplayTransformHint = display->getTransformHint();
}
}
if (currentState.width != drawingState.width ||
currentState.height != drawingState.height) {
display->setDisplaySize(currentState.width, currentState.height); //设置显示器尺寸
if (isDisplayActiveLocked(display)) {
onActiveDisplaySizeChanged(display);
}
}
}
}
SurfaceFlinger processDisplayAdded
调用processDisplayAdded方法，处理显示器添加：
//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));
}
SurfaceFlinger doCommitTransactions
调用SurfaceFlinger的doCommitTransactions方法：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::doCommitTransactions() {
ATRACE_CALL();
if (!mLayersPendingRemoval.isEmpty()) {
// Notify removed layers now that they can't be drawn from
for (const auto& l : mLayersPendingRemoval) {
// Ensure any buffers set to display on any children are released.
if (l->isRemovedFromCurrentState()) {
l->latchAndReleaseBuffer();
}
// If a layer has a parent, we allow it to out-live it's handle
// with the idea that the parent holds a reference and will eventually
// be cleaned up. However no one cleans up the top-level so we do so
// here.
if (l->isAtRoot()) {
l->setIsAtRoot(false);
mCurrentState.layersSortedByZ.remove(l);
}
// If the layer has been removed and has no parent, then it will not be reachable
// when traversing layers on screen. Add the layer to the offscreenLayers set to
// ensure we can copy its current to drawing state.
if (!l->getParent()) {
mOffscreenLayers.emplace(l.get());
}
}
mLayersPendingRemoval.clear();
}
// If this transaction is part of a window animation then the next frame
// we composite should be considered an animation as well.
//最关键mCurrentState赋值给了mDrawingState
mAnimCompositionPending = mAnimTransactionPending;
mDrawingState = mCurrentState;
// clear the "changed" flags in current state
mCurrentState.colorMatrixChanged = false;
if (mVisibleRegionsDirty) {
for (const auto& rootLayer : mDrawingState.layersSortedByZ) {
rootLayer->commitChildList();
}
}
commitOffscreenLayers();
if (mNumClones > 0) {
mDrawingState.traverse([&](Layer* layer) { layer->updateMirrorInfo(); });
}
}
SurfaceFlinger latchBuffers
调用SurfaceFlinger的latchBuffers方法，将应用程序的图形缓冲区（buffer）与显示器进行关联：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
bool SurfaceFlinger::latchBuffers() {
ATRACE_CALL();
const nsecs_t latchTime = systemTime();
bool visibleRegions = false;
bool frameQueued = false;
bool newDataLatched = false;
const nsecs_t expectedPresentTime = mExpectedPresentTime.load();
// Store the set of layers that need updates. This set must not change as
// buffers are being latched, as this could result in a deadlock.
// Example: Two producers share the same command stream and:
// 1.) Layer 0 is latched
// 2.) Layer 0 gets a new frame
// 2.) Layer 1 gets a new frame
// 3.) Layer 1 is latched.
// Display is now waiting on Layer 1's frame, which is behind layer 0's
// second frame. But layer 0's second frame could be waiting on display.
mDrawingState.traverse([&](Layer* layer) {
if (layer->clearTransactionFlags(eTransactionNeeded) || mForceTransactionDisplayChange) {
const uint32_t flags = layer->doTransaction(0);
if (flags & Layer::eVisibleRegion) {
mVisibleRegionsDirty = true;
}
}
//判断是否有buffer
if (layer->hasReadyFrame()) {
frameQueued = true;
//是否应该显示
if (layer->shouldPresentNow(expectedPresentTime)) {
//如果要显示放入到mLayersWithQueuedFrames队列
mLayersWithQueuedFrames.emplace(layer);
} else {
ATRACE_NAME("!layer->shouldPresentNow()");
layer->useEmptyDamage();
}
} else {
layer->useEmptyDamage();
}
});
//上面主要是为了从sf的mDrawingState遍历寻找出有buffer的layer
mForceTransactionDisplayChange = false;
// The client can continue submitting buffers for offscreen layers, but they will not
// be shown on screen. Therefore, we need to latch and release buffers of offscreen
// layers to ensure dequeueBuffer doesn't block indefinitely.
for (Layer* offscreenLayer : mOffscreenLayers) {
offscreenLayer->traverse(LayerVector::StateSet::Drawing,
[&](Layer* l) { l->latchAndReleaseBuffer(); });
}
//如果buffer队列不为空
if (!mLayersWithQueuedFrames.empty()) {
// mStateLock is needed for latchBuffer as LayerRejecter::reject()
// writes to Layer current state. See also b/119481871
Mutex::Autolock lock(mStateLock);
for (const auto& layer : mLayersWithQueuedFrames) {
//进行关键的latchBuffer操作,然后newDataLatched设置成了true
if (layer->latchBuffer(visibleRegions, latchTime, expectedPresentTime)) {
mLayersPendingRefresh.push_back(layer); /这里有latchBuffer说明有buffer刷新，放入mLayersPendingRefresh
newDataLatched = true;
}
layer->useSurfaceDamage();
}
}
mVisibleRegionsDirty |= visibleRegions;
// If we will need to wake up at some time in the future to deal with a
// queued frame that shouldn't be displayed during this vsync period, wake
// up during the next vsync period to check again.
if (frameQueued && (mLayersWithQueuedFrames.empty() || !newDataLatched)) {
scheduleCommit(FrameHint::kNone);
}
// enter boot animation on first buffer latch
if (CC_UNLIKELY(mBootStage == BootStage::BOOTLOADER && newDataLatched)) {
ALOGI("Enter boot animation");
mBootStage = BootStage::BOOTANIMATION;
}
if (mNumClones > 0) {
mDrawingState.traverse([&](Layer* layer) { layer->updateCloneBufferInfo(); });
}
// Only continue with the refresh if there is actually new work to do
return !mLayersWithQueuedFrames.empty() && newDataLatched;
}
BufferLayer latchBuffer
调用layer的latchBuffer方法：
//frameworks/native/services/surfaceflinger/BufferLayer.cpp
bool BufferLayer::latchBuffer(bool& recomputeVisibleRegions, nsecs_t latchTime,
nsecs_t expectedPresentTime) {
ATRACE_CALL();
bool refreshRequired = latchSidebandStream(recomputeVisibleRegions);
if (refreshRequired) {
return refreshRequired;
}
// If the head buffer's acquire fence hasn't signaled yet, return and
// try again later
// 如果头部缓冲区的采集围栏尚未发出信号，请返回并稍后重试
if (!fenceHasSignaled()) {
ATRACE_NAME("!fenceHasSignaled()");
mFlinger->onLayerUpdate(); // (692) SurfaceFlinger onLayerUpdate流程分析 | 知识管理 - PingCode
return false;
}
// Capture the old state of the layer for comparisons later
const State& s(getDrawingState());
const bool oldOpacity = isOpaque(s);
BufferInfo oldBufferInfo = mBufferInfo;
//调用到BufferStateLayer中的updateTexImage，这里业务主要返回对应的recomputeVisibleRegions
status_t err = updateTexImage(recomputeVisibleRegions, latchTime, expectedPresentTime);
if (err != NO_ERROR) {
return false;
}
//这里主要吧state的相关buffer数据赋值给mBufferInfo
err = updateActiveBuffer();
if (err != NO_ERROR) {
return false;
}
//赋值一下framenumber
err = updateFrameNumber();
if (err != NO_ERROR) {
return false;
}
//这里又一次吧mDrawingState中BufferInfo需要的大部分数据进行赋值
gatherBufferInfo();
if (oldBufferInfo.mBuffer == nullptr) {
// the first time we receive a buffer, we need to trigger a
// geometry invalidation.
recomputeVisibleRegions = true;
}
if ((mBufferInfo.mCrop != oldBufferInfo.mCrop) ||
(mBufferInfo.mTransform != oldBufferInfo.mTransform) ||
(mBufferInfo.mScaleMode != oldBufferInfo.mScaleMode) ||
(mBufferInfo.mTransformToDisplayInverse != oldBufferInfo.mTransformToDisplayInverse)) {
recomputeVisibleRegions = true;
}
if (oldBufferInfo.mBuffer != nullptr) {
uint32_t bufWidth = mBufferInfo.mBuffer->getWidth();
uint32_t bufHeight = mBufferInfo.mBuffer->getHeight();
if (bufWidth != oldBufferInfo.mBuffer->getWidth() ||
bufHeight != oldBufferInfo.mBuffer->getHeight()) {
recomputeVisibleRegions = true;
}
}
if (oldOpacity != isOpaque(s)) {
recomputeVisibleRegions = true;
}
return true;
}
BufferQueueLayer updateTexImage
调用BufferLayer的updateTexImage方法，BufferQueueLayer继承与于BufferLayer，调用BufferQueueLayer的updateTexImage方法：
Android13 BufferQueueLayer updateTexImage流程分析-优快云博客
SurfaceFlinger updateLayerGeometry
调用SurfaceFlinger的updateLayerGeometry方法，这次vsync显示刷新的layer进行脏区设置：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::updateLayerGeometry() {
ATRACE_CALL();
if (mVisibleRegionsDirty) {
computeLayerBounds(); //触发各个layer计算对于的bound
}
//前面有buffer的集合mLayersPendingRefresh进行对应display的dirtyRegion更新
for (auto& layer : mLayersPendingRefresh) {
Region visibleReg;
visibleReg.set(layer->getScreenBounds());
invalidateLayerStack(layer, visibleReg); //刷新一下display的dirtyRegion
}
mLayersPendingRefresh.clear();
}
SurfaceFlinger invalidateLayerStack
调用SurfaceFlinger的invalidateLayerStack方法：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::invalidateLayerStack(const sp<const Layer>& layer, const Region& dirty) {
for (const auto& [token, displayDevice] : FTL_FAKE_GUARD(mStateLock, mDisplays)) {
auto display = displayDevice->getCompositionDisplay();
if (display->includesLayer(layer->getOutputFilter())) { //寻找到对应的display
display->editState().dirtyRegion.orSelf(dirty); //设置到了display->editState中
}
}
}
上面主要就是干了一件事，根据这次有buffer的Layer进行遍历，刷新对应display的dirtyRegion。
SurfaceFlinger updateInputFlinger
调用SurfaceFlinger的updateInputFlinger方法，更新输入处理：
//frameworks/native/services/surfaceflinger/Surfaceflinger.cpp
void SurfaceFlinger::updateInputFlinger() {
ATRACE_CALL();
if (!mInputFlinger) {
return;
}
std::vector<WindowInfo> windowInfos;
std::vector<DisplayInfo> displayInfos;
bool updateWindowInfo = false;
if (mVisibleRegionsDirty || mInputInfoChanged) {
mInputInfoChanged = false;
updateWindowInfo = true;
//进行遍历整个系统的layer和display转变成windowInfos，displayInfos信息
buildWindowInfos(windowInfos, displayInfos);
}
if (!updateWindowInfo && mInputWindowCommands.empty()) {
return;
}
//这里放入子线程进行相对应跨进程通讯
BackgroundExecutor::getInstance().sendCallbacks({[updateWindowInfo,
windowInfos = std::move(windowInfos),
displayInfos = std::move(displayInfos),
inputWindowCommands =
std::move(mInputWindowCommands),
inputFlinger = mInputFlinger, this]() {
ATRACE_NAME("BackgroundExecutor::updateInputFlinger");
if (updateWindowInfo) {
//这里调用是mWindowInfosListenerInvoker进行的windowInfos, displayInfos进行跨进程传递
mWindowInfosListenerInvoker->windowInfosChanged(windowInfos, displayInfos,
inputWindowCommands.syncInputWindows);
} else if (inputWindowCommands.syncInputWindows) {
// If the caller requested to sync input windows, but there are no
// changes to input windows, notify immediately.
windowInfosReported();
}
for (const auto& focusRequest : inputWindowCommands.focusRequests) {
//直接调用inputFlinger的bpbinder跨进程设置setFocusedWindow
inputFlinger->setFocusedWindow(focusRequest);
}
}});
mInputWindowCommands.clear();
}
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