标签：12 const 合成 hardware FramebufferSurface SurfaceFlinger 227 android
必读：
Android 12(S) 图像显示系统 - 开篇
一、前言
SurfaceFlinger中的图层选择GPU合成(CLIENT合成方式)时，会把待合成的图层Layers通过renderengine(SkiaGLRenderEngine)绘制到一块GraphicBuffer中，然后把这块GraphicBuffer图形缓存通过调用setClientTarget传递给HWC模块，HWC进一步处理后把这个GraphicBuffer中的图像呈现到屏幕上。
本篇文章，我们先聚焦一点做介绍：用于存储GPU合成后的图形数据的GraphicBuffer是从哪里来的？下面的讲解会围绕这个问题展开。
二、从dumpsys SurfaceFlinger中的信息谈起
如果你查看过dumpsys SurfaceFlinger的信息，也许你注意过一些GraphicBufferAllocator/GraphicBufferMapper打印出的一些信息，这些信息记录了所有通过Gralloc模块allocate和import的图形缓存的信息。
如下是在我的平台下截取的dumpsys SurfaceFlinger部分信息：
GraphicBufferAllocator buffers:
Handle | Size | W (Stride) x H | Layers | Format | Usage | Requestor
0xf3042b90 | 8100.00 KiB | 1920 (1920) x 1080 | 1 | 1 | 0x 1b00 | FramebufferSurface
0xf3042f30 | 8100.00 KiB | 1920 (1920) x 1080 | 1 | 1 | 0x 1b00 | FramebufferSurface
0xf3046020 | 8100.00 KiB | 1920 (1920) x 1080 | 1 | 1 | 0x 1b00 | FramebufferSurface
Total allocated by GraphicBufferAllocator (estimate): 24300.00 KB
Imported gralloc buffers:
+ name:FramebufferSurface, id:e100000000, size:8.3e+03KiB, w/h:780x438, usage: 0x40001b00, req fmt:5, fourcc/mod:875713089/576460752303423505, dataspace: 0x0, compressed: true
planes: B/G/R/A: w/h:780x440, stride:1e00 bytes, size:818000
+ name:FramebufferSurface, id:e100000001, size:8.3e+03KiB, w/h:780x438, usage: 0x40001b00, req fmt:5, fourcc/mod:875713089/576460752303423505, dataspace: 0x0, compressed: true
planes: B/G/R/A: w/h:780x440, stride:1e00 bytes, size:818000
+ name:FramebufferSurface, id:e100000002, size:8.3e+03KiB, w/h:780x438, usage: 0x40001b00, req fmt:5, fourcc/mod:875713089/576460752303423505, dataspace: 0x0, compressed: true
planes: B/G/R/A: w/h:780x440, stride:1e00 bytes, size:818000
Total imported by gralloc: 5e+04KiB上面的信息中可以看到一些儿冥冥之中貌似、似乎、好像很有意思的字眼：FramebufferSurface。
作为Requestor的FramebufferSurface去请求分配了三块图形缓存，还规定了width、height、format、usage等信息。
如上你看到的这3块GraphicBuffer，就是用来存储CPU合成后的图形数据的。
三、创建与初始化FramebufferSurface的流程
FramebufferSurface的初始化逻辑需要从SurfaceFlinger的初始化谈起，在文章Android 12(S) 图像显示系统 - SurfaceFlinger的启动和消息队列处理机制（四）
中，曾分析过，SurfaceFlinger::init()中会去注册HWC的回调函数mCompositionEngine->getHwComposer().setCallback(this)，当第一次注册callback时，onComposerHalHotplug()会立即在调用registerCallback()的线程中被调用，并跨进程回调到SurfaceFlinger::onComposerHalHotplug。然后一路飞奔：
在SurfaceFlinger::processDisplayAdded这个方法中去创建了BufferQueue和FramebufferSurface，简单理解为连接上了显示屏幕(Display)，那就要给准备一个BufferQueue，以便GPU合成UI等图层时，可以向这个BufferQueue索要GraphicBuffer来存储合成后的图形数据，再呈现到屏幕上去（我的傻瓜式理解）
摘取关键代码如下：
[/frameworks/native/services/surfaceflinger/SurfaceFlinger.cpp]
void SurfaceFlinger::processDisplayAdded(const wp<IBinder>& displayToken,
const DisplayDeviceState& state) {
......
sp<compositionengine::DisplaySurface> displaySurface;
sp<IGraphicBufferProducer> producer;
// 创建BufferQueue,获取到生产者和消费者，而且消费者不是SurfaceFlinger哦
sp<IGraphicBufferProducer> bqProducer;
sp<IGraphicBufferConsumer> bqConsumer;
getFactory().createBufferQueue(&bqProducer, &bqConsumer, /*consumerIsSurfaceFlinger =*/false);
if (state.isVirtual()) { // 虚拟屏幕，不管它
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 { // 看这个case
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);
// 创建了FramebufferSurface对象，FramebufferSurface继承自compositionengine::DisplaySurface
// FramebufferSurface是作为消费者的角色工作的，消费SF GPU合成后的图形数据
displaySurface =
sp<FramebufferSurface>::make(getHwComposer(), *displayId, bqConsumer,
state.physical->activeMode->getSize(),
ui::Size(maxGraphicsWidth, maxGraphicsHeight));
producer = bqProducer;
}
LOG_FATAL_IF(!displaySurface);
// 创建DisplayDevice，其又去创建RenderSurface，作为生产者角色工作，displaySurface就是FramebufferSurface对象
const auto display = setupNewDisplayDeviceInternal(displayToken, std::move(compositionDisplay),
state, displaySurface, producer);
mDisplays.emplace(displayToken, display);
......
}瞅一瞅 FramebufferSuraface的构造函数，没啥复杂的，就是一些设置，初始化一些成员
FramebufferSurface::FramebufferSurface(HWComposer& hwc, PhysicalDisplayId displayId,
const sp<IGraphicBufferConsumer>& consumer,
const ui::Size& size, const ui::Size& maxSize)
: ConsumerBase(consumer),
mDisplayId(displayId),
mMaxSize(maxSize),
mCurrentBufferSlot(-1),
mCurrentBuffer(),
mCurrentFence(Fence::NO_FENCE),
mHwc(hwc),
mHasPendingRelease(false),
mPreviousBufferSlot(BufferQueue::INVALID_BUFFER_SLOT),
mPreviousBuffer() {
ALOGV("Creating for display %s", to_string(displayId).c_str());
mName = "FramebufferSurface";
mConsumer->setConsumerName(mName); // 设置消费者的名字是 "FramebufferSurface"
mConsumer->setConsumerUsageBits(GRALLOC_USAGE_HW_FB | // 设置usage
GRALLOC_USAGE_HW_RENDER |
GRALLOC_USAGE_HW_COMPOSER);
const auto limitedSize = limitSize(size);
mConsumer->setDefaultBufferSize(limitedSize.width, limitedSize.height); // 设置buffer 大小
mConsumer->setMaxAcquiredBufferCount(
SurfaceFlinger::maxFrameBufferAcquiredBuffers - 1);
}
再进到SurfaceFlinger::setupNewDisplayDeviceInternal中看看相关的逻辑：
[/frameworks/native/services/surfaceflinger/SurfaceFlinger.cpp]
sp<DisplayDevice> SurfaceFlinger::setupNewDisplayDeviceInternal(
const wp<IBinder>& displayToken,
std::shared_ptr<compositionengine::Display> compositionDisplay,
const DisplayDeviceState& state,
const sp<compositionengine::DisplaySurface>& displaySurface,
const sp<IGraphicBufferProducer>& producer) {
......
creationArgs.displaySurface = displaySurface; // displaySurface就是FramebufferSurface对象
// producer是前面processDisplayAdded中创建的
auto nativeWindowSurface = getFactory().createNativeWindowSurface(producer);
auto nativeWindow = nativeWindowSurface->getNativeWindow();
creationArgs.nativeWindow = nativeWindow;
....
// 前面一大坨代码是在初始话creationArgs，这些参数用来创建DisplayDevice
// creationArgs.nativeWindow会把前面创建的producer关联到了DisplayDevice
sp<DisplayDevice> display = getFactory().createDisplayDevice(creationArgs);
// 后面一大坨，对display进行了些设置
if (!state.isVirtual()) {
display->setActiveMode(state.physical->activeMode->getId());
display->setDeviceProductInfo(state.physical->deviceProductInfo);
}
....
}
接下来就是 DisplayDevice 的构造函数了，里面主要是创建了RenderSurface对象，然后对其进行初始化
[/frameworks/native/services/surfaceflinger/DisplayDevice.cpp]
DisplayDevice::DisplayDevice(DisplayDeviceCreationArgs& args)
: mFlinger(args.flinger),
mHwComposer(args.hwComposer),
mDisplayToken(args.displayToken),
mSequenceId(args.sequenceId),
mConnectionType(args.connectionType),
mCompositionDisplay{args.compositionDisplay},
mPhysicalOrientation(args.physicalOrientation),
mSupportedModes(std::move(args.supportedModes)),
mIsPrimary(args.isPrimary) {
mCompositionDisplay->editState().isSecure = args.isSecure;
// 创建RenderSurface，args.nativeWindow 即为producer,指向生产者
mCompositionDisplay->createRenderSurface(
compositionengine::RenderSurfaceCreationArgsBuilder()
.setDisplayWidth(ANativeWindow_getWidth(args.nativeWindow.get()))
.setDisplayHeight(ANativeWindow_getHeight(args.nativeWindow.get()))
.setNativeWindow(std::move(args.nativeWindow))
.setDisplaySurface(std::move(args.displaySurface)) // displaySurface就是FramebufferSurface对象
.setMaxTextureCacheSize(
static_cast<size_t>(SurfaceFlinger::maxFrameBufferAcquiredBuffers))
.build());
if (!mFlinger->mDisableClientCompositionCache &&
SurfaceFlinger::maxFrameBufferAcquiredBuffers > 0) {
mCompositionDisplay->createClientCompositionCache(
static_cast<uint32_t>(SurfaceFlinger::maxFrameBufferAcquiredBuffers));
}
mCompositionDisplay->createDisplayColorProfile(
compositionengine::DisplayColorProfileCreationArgs{args.hasWideColorGamut,
std::move(args.hdrCapabilities),
args.supportedPerFrameMetadata,
args.hwcColorModes});
if (!mCompositionDisplay->isValid()) {
ALOGE("Composition Display did not validate!");
}
// 初始化RenderSurface
mCompositionDisplay->getRenderSurface()->initialize();
setPowerMode(args.initialPowerMode);
// initialize the display orientation transform.
setProjection(ui::ROTATION_0, Rect::INVALID_RECT, Rect::INVALID_RECT);
}本文作者@二的次方 2022-05-10 发布于博客园
RenderSurface作为生产者的角色工作，构造函数如下，留意启成员displaySurface就是SurfaceFlinger中创建的FramebufferSurface对象
也就是 作为生产者的RenderSurface中持有 消费者的引用 displaySurface，可以呼叫FramebufferSurface的方法
[ /frameworks/native/services/surfaceflinger/CompositionEngine/src/RenderSurface.cpp]
RenderSurface::RenderSurface(const CompositionEngine& compositionEngine, Display& display,
const RenderSurfaceCreationArgs& args)
: mCompositionEngine(compositionEngine),
mDisplay(display),
mNativeWindow(args.nativeWindow),
mDisplaySurface(args.displaySurface), // displaySurface就是FramebufferSurface对象
mSize(args.displayWidth, args.displayHeight),
mMaxTextureCacheSize(args.maxTextureCacheSize) {
LOG_ALWAYS_FATAL_IF(!mNativeWindow);
}
我们看看他的RenderSurface::initialize()方法
[/frameworks/native/services/surfaceflinger/CompositionEngine/src/RenderSurface.cpp]
void RenderSurface::initialize() {
ANativeWindow* const window = mNativeWindow.get();
int status = native_window_api_connect(window, NATIVE_WINDOW_API_EGL);
ALOGE_IF(status != NO_ERROR, "Unable to connect BQ producer: %d", status);
status = native_window_set_buffers_format(window, HAL_PIXEL_FORMAT_RGBA_8888);
ALOGE_IF(status != NO_ERROR, "Unable to set BQ format to RGBA888: %d", status);
status = native_window_set_usage(window, DEFAULT_USAGE);
ALOGE_IF(status != NO_ERROR, "Unable to set BQ usage bits for GPU rendering: %d", status);
}上述方法也很简单，就是作为producer去和BufferQueue建立connect，并设置format为RGBA_8888，设置usage为GRALLOC_USAGE_HW_RENDER | GRALLOC_USAGE_HW_TEXTURE
为了验证上述分析的流程是正确的，我在BufferQueueProducer::connect中加log来打印调用栈的信息，如下，是不是和分析的一样啊
11-13 00:52:58.497 227 227 D BufferQueueProducer: connect[1303] /vendor/bin/hw/android.hardware.graphics.composer@2.4-service start
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#00 pc 0005e77f /system/lib/libgui.so (android::BufferQueueProducer::connect(android::sp<android::IProducerListener> const&, int, bool, android::IGraphicBufferProducer::QueueBufferOutput*)+1282)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#01 pc 000a276b /system/lib/libgui.so (android::Surface::connect(int, android::sp<android::IProducerListener> const&, bool)+138)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#02 pc 0009de41 /system/lib/libgui.so (android::Surface::hook_perform(ANativeWindow*, int, ...)+128)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#03 pc 00121b1d /system/bin/surfaceflinger (android::compositionengine::impl::RenderSurface::initialize()+12)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#04 pc 00083cc5 /system/bin/surfaceflinger (android::DisplayDevice::DisplayDevice(android::DisplayDeviceCreationArgs&)+1168)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#05 pc 000d8bed /system/bin/surfaceflinger (android::SurfaceFlinger::processDisplayAdded(android::wp<android::IBinder> const&, android::DisplayDeviceState const&)+4440)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#06 pc 000d0db5 /system/bin/surfaceflinger (android::SurfaceFlinger::processDisplayChangesLocked()+2436)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#07 pc 000cef6b /system/bin/surfaceflinger (android::SurfaceFlinger::processDisplayHotplugEventsLocked()+6422)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#08 pc 000d2c7f /system/bin/surfaceflinger (android::SurfaceFlinger::onComposerHalHotplug(unsigned long long, android::hardware::graphics::composer::V2_1::IComposerCallback::Connection)+334)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#09 pc 0009afab /system/bin/surfaceflinger (_ZN7android12_GLOBAL__N_122ComposerCallbackBridge9onHotplugEyNS_8hardware8graphics8composer4V2_117IComposerCallback10ConnectionE$d689f7ac1c60e4abeed02ca92a51bdcd+20)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#10 pc 0001bb97 /system/lib/android.hardware.graphics.composer@2.1.so (android::hardware::graphics::composer::V2_1::BnHwComposerCallback::_hidl_onHotplug(android::hidl::base::V1_0::BnHwBase*, android::hardware::Parcel const&, android::hardware::Parcel*, std::__1::function<void (android::hardware::Parcel&)>)+166)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#11 pc 000275e9 /system/lib/android.hardware.graphics.composer@2.4.so (android::hardware::graphics::composer::V2_4::BnHwComposerCallback::onTransact(unsigned int, android::hardware::Parcel const&, android::hardware::Parcel*, unsigned int, std::__1::function<void (android::hardware::Parcel&)>)+228)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#12 pc 00054779 /system/lib/libhidlbase.so (android::hardware::BHwBinder::transact(unsigned int, android::hardware::Parcel const&, android::hardware::Parcel*, unsigned int, std::__1::function<void (android::hardware::Parcel&)>)+96)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#13 pc 0004fc67 /system/lib/libhidlbase.so (android::hardware::IPCThreadState::transact(int, unsigned int, android::hardware::Parcel const&, android::hardware::Parcel*, unsigned int)+2174)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#14 pc 0004f2e5 /system/lib/libhidlbase.so (android::hardware::BpHwBinder::transact(unsigned int, android::hardware::Parcel const&, android::hardware::Parcel*, unsigned int, std::__1::function<void (android::hardware::Parcel&)>)+36)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#15 pc 0002bdf1 /system/lib/android.hardware.graphics.composer@2.4.so (android::hardware::graphics::composer::V2_4::BpHwComposerClient::_hidl_registerCallback_2_4(android::hardware::IInterface*, android::hardware::details::HidlInstrumentor*, android::sp<android::hardware::graphics::composer::V2_4::IComposerCallback> const&)+296)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#16 pc 0002ed8d /system/lib/android.hardware.graphics.composer@2.4.so (android::hardware::graphics::composer::V2_4::BpHwComposerClient::registerCallback_2_4(android::sp<android::hardware::graphics::composer::V2_4::IComposerCallback> const&)+34)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#17 pc 00085627 /system/bin/surfaceflinger (android::Hwc2::impl::Composer::registerCallback(android::sp<android::hardware::graphics::composer::V2_4::IComposerCallback> const&)+98)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#18 pc 00092d63 /system/bin/surfaceflinger (android::impl::HWComposer::setCallback(android::HWC2::ComposerCallback*)+2206)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#19 pc 000cd35b /system/bin/surfaceflinger (android::SurfaceFlinger::init()+438)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#20 pc 000feb03 /system/bin/surfaceflinger (main+862)
11-13 00:52:58.581 227 227 E BufferQueueProducer: stackdump:#21 pc 0003253b /apex/com.android.runtime/lib/bionic/libc.so (__libc_init+54)
11-13 00:52:58.582 227 227 D BufferQueueProducer: connect[1307] /vendor/bin/hw/android.hardware.graphics.composer@2.4-service end注意 本文作者@二的次方 2022-05-10 发布于博客园
注意 本文作者@二的次方 2022-05-10 发布于博客园
注意 本文作者@二的次方 2022-05-10 发布于博客园
这里有一个小细节要留意下，因为SurfaceFlinger::onComposerHalHotplug是HWC回调过来的，所以代码执行是在android.hardware.graphics.composer@2.4-service这个进程中的。
BufferQueueProducer::connect中记录的mConnectedPid就是composer service的PID
[ /frameworks/native/libs/gui/BufferQueueProducer.cpp]
mCore->mConnectedPid = BufferQueueThreadState::getCallingPid();在dump BufferQueue的信息时，根据PID获取的 producer name 也就是 android.hardware.graphics.composer@2.4-service
[/frameworks/native/libs/gui/BufferQueueCore.cpp]
void BufferQueueCore::dumpState(const String8& prefix, String8* outResult) const {
...
getProcessName(mConnectedPid, producerProcName);
getProcessName(pid, consumerProcName);
....
}如下是我的平台dumpsys SurfaceFlinger的信息打印出来的Composition RenderSurface State的信息，看看是不是和代码的设置都有对应起来：
标签：12,const,合成,hardware,FramebufferSurface,SurfaceFlinger,227,android 来源： https://www.cnblogs.com/roger-yu/p/16230337.html
本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享； 2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关； 3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关； 4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除； 5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。