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| //frameworks/native/services/surfaceflinger/BufferQueueLayer.cpp
status_t BufferQueueLayer::updateTexImage(bool& recomputeVisibleRegions, nsecs_t latchTime,
nsecs_t expectedPresentTime) {
// This boolean is used to make sure that SurfaceFlinger's shadow copy
// of the buffer queue isn't modified when the buffer queue is returning
// BufferItem's that weren't actually queued. This can happen in shared
// buffer mode.
bool queuedBuffer = false;
const int32_t layerId = getSequence();
LayerRejecter r(mDrawingState, getDrawingState(), recomputeVisibleRegions,
getProducerStickyTransform() != 0, mName,
getTransformToDisplayInverse());
if (isRemovedFromCurrentState()) {
expectedPresentTime = 0;
}
// updateTexImage() below might drop the some buffers at the head of the queue if there is a
// buffer behind them which is timely to be presented. However this buffer may not be signaled
// yet. The code below makes sure that this wouldn't happen by setting maxFrameNumber to the
// last buffer that was signaled.
uint64_t lastSignaledFrameNumber = mLastFrameNumberReceived;
{
Mutex::Autolock lock(mQueueItemLock);
for (size_t i = 0; i < mQueueItems.size(); i++) {
bool fenceSignaled =
mQueueItems[i].item.mFenceTime->getSignalTime() != Fence::SIGNAL_TIME_PENDING;
if (!fenceSignaled) {
break;
}
lastSignaledFrameNumber = mQueueItems[i].item.mFrameNumber;
}
}
const uint64_t maxFrameNumberToAcquire =
std::min(mLastFrameNumberReceived.load(), lastSignaledFrameNumber);
bool autoRefresh;
status_t updateResult = mConsumer->updateTexImage(&r, expectedPresentTime, &autoRefresh,
&queuedBuffer, maxFrameNumberToAcquire);
mDrawingState.autoRefresh = autoRefresh;
if (updateResult == BufferQueue::PRESENT_LATER) {
// Producer doesn't want buffer to be displayed yet. Signal a
// layer update so we check again at the next opportunity.
// Producer 不希望显示缓冲区。 发出图层更新的信号，以便我们在下次有机会时再次检查。
mFlinger->onLayerUpdate(); // (692) SurfaceFlinger onLayerUpdate流程分析
return BAD_VALUE;
} else if (updateResult == BufferLayerConsumer::BUFFER_REJECTED) {
// If the buffer has been rejected, remove it from the shadow queue
// and return early
if (queuedBuffer) {
Mutex::Autolock lock(mQueueItemLock);
if (mQueuedFrames > 0) {
mConsumer->mergeSurfaceDamage(mQueueItems[0].item.mSurfaceDamage);
mFlinger->mTimeStats->removeTimeRecord(layerId, mQueueItems[0].item.mFrameNumber);
if (mQueueItems[0].surfaceFrame) {
addSurfaceFrameDroppedForBuffer(mQueueItems[0].surfaceFrame);
}
mQueueItems.erase(mQueueItems.begin());
mQueuedFrames--;
}
}
return BAD_VALUE;
} else if (updateResult != NO_ERROR || mUpdateTexImageFailed) {
// This can occur if something goes wrong when trying to create the
// EGLImage for this buffer. If this happens, the buffer has already
// been released, so we need to clean up the queue and bug out
// early.
if (queuedBuffer) {
Mutex::Autolock lock(mQueueItemLock);
for (auto& [item, surfaceFrame] : mQueueItems) {
if (surfaceFrame) {
addSurfaceFrameDroppedForBuffer(surfaceFrame);
}
}
mQueueItems.clear();
mQueuedFrames = 0;
mFlinger->mTimeStats->onDestroy(layerId);
mFlinger->mFrameTracer->onDestroy(layerId);
}
// Once we have hit this state, the shadow queue may no longer
// correctly reflect the incoming BufferQueue's contents, so even if
// updateTexImage starts working, the only safe course of action is
// to continue to ignore updates.
mUpdateTexImageFailed = true;
return BAD_VALUE;
}
bool more_frames_pending = false;
if (queuedBuffer) {
// Autolock scope
auto currentFrameNumber = mConsumer->getFrameNumber();
Mutex::Autolock lock(mQueueItemLock);
// Remove any stale buffers that have been dropped during
// updateTexImage
while (mQueuedFrames > 0 && mQueueItems[0].item.mFrameNumber != currentFrameNumber) {
mConsumer->mergeSurfaceDamage(mQueueItems[0].item.mSurfaceDamage);
mFlinger->mTimeStats->removeTimeRecord(layerId, mQueueItems[0].item.mFrameNumber);
if (mQueueItems[0].surfaceFrame) {
addSurfaceFrameDroppedForBuffer(mQueueItems[0].surfaceFrame);
}
mQueueItems.erase(mQueueItems.begin());
mQueuedFrames--;
}
uint64_t bufferID = mQueueItems[0].item.mGraphicBuffer->getId();
mFlinger->mTimeStats->setLatchTime(layerId, currentFrameNumber, latchTime);
mFlinger->mFrameTracer->traceTimestamp(layerId, bufferID, currentFrameNumber, latchTime,
FrameTracer::FrameEvent::LATCH);
if (mQueueItems[0].surfaceFrame) {
addSurfaceFramePresentedForBuffer(mQueueItems[0].surfaceFrame,
mQueueItems[0].item.mFenceTime->getSignalTime(),
latchTime);
}
mQueueItems.erase(mQueueItems.begin());
more_frames_pending = (mQueuedFrames.fetch_sub(1) > 1);
}
// Decrement the queued-frames count. Signal another event if we
// have more frames pending.
//减少排队的帧计数。 如果我们有更多待处理的帧，则发出另一个事件的信号。
if ((queuedBuffer && more_frames_pending) || mDrawingState.autoRefresh) {
mFlinger->onLayerUpdate(); // (692) SurfaceFlinger onLayerUpdate流程分析 | 知识管理 - PingCode
}
return NO_ERROR;
}
|
wentao