Cubietruck — 20.SurfaceFlinger creation process analysis

1. The startup process of surfaceFlinger
1.Prevent system_init from starting SF
in init.rc

Now that it says to prevent system_init from starting surfaceFlinger, let’s see how to stop it.
in frameworks/base/cmds/system_server/library/system_init.cpp

Get system_init.startsurfaceflinger The value of this attribute, if If it is 1, start sf.
But if this attribute value is set to 0 in init.rc, this will not start sf.
2. SF’s real startup process
still in init.rc

in frameworks/native/cmds/surfaceflinger/main_surfaceflinger.cpp

in frameworks/native/include/binder/BinderService.h

The new SERVICE is a new surfaceflinger, enter the constructor of surfaceflinger < br style="word-wrap:break-word; color:rgb(102,102,102); font-family:宋体,Arial; font-size:16px; line-height:26px"> 3. onFirstRef starts the main thread
Because SurfaceFlinger inherits from class Thread, Thread inherits from RefBase
In frameworks/native/include/utils/Thread.h, class Thread: virtual public RefBase

a. 初始化egl
b. 新建 HWComposer
c. 新建 DisplayDevice
    

1. DisplayDevice::DisplayDevice(const sp<SurfaceFlinger>& flinger, …)
   
2. {
   
3.     init(config);
4.     mDisplayDispatcher = new DisplayDispatcher(mFlinger); //新建一个DisplayDispatcher
   
5. }

1. # Set this property so surfaceflinger is not started by system_init
   
2.     setprop system_init.startsurf aceflinger 0

1. extern “C” status_t system_init()
   
2. {
3.     char propBuf[PROPERTY_VAL UE_MAX];
   
4.     property_get(“system_init.startsurfaceflinger”, propBuf, “1”);
   
5.     if (strcmp(propBuf, “1”) == 0) {
   
6.         SurfaceFlinger::instantiate( );
   
7.     } 
   
8. }
   

1. service surfaceflinger /system/bin/surfaceflinger
   
2.     class main
   
3.     user system
   
4.     group graphics
   
5.     onrestart restart zygote

1. int main(int argc, char** argv) {
   
2.     SurfaceFlinger::publishAndJoinThreadPool(true);
   
3.     ProcessState::self()–>setThreadPoolMaxThreadCount(4);
   
4.     return 0;
   
5. }

1. static void publishAndJoinThreadPool(bool allowIsolated = false) {
   
2.     sp<IServiceManager> sm(defaultServiceManager());
   
3.     sm–>addService(String16(SERVICE::getServiceName()), new SERVICE(), allowIsolated);
   
4.     ProcessState::self()–>startThreadPool();
   
5.     IPCThreadState::self()–>joinThreadPool();
   
6. }

1. void SurfaceFlinger::onFirstRef()
   
2. {
   
3.     mEventQueue.init(this);              //消息队列初始化
   
4.     run(“SurfaceFlinger”, PRIORITY_URGENT_DISPLAY);  //启动工作线程
   
5.     mReadyToRunBarrier.wait(< span style="word-wrap:break-word; color:rgb(0,0,204)">);   //等侍标志
   
6. }

1. status_t SurfaceFlinger::readyToRun()
   
2. {
   
3.     mEGLDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
   
4.     eglInitialize(mEGLDisplay, NULL , NULL);
5. 
   
6.     mHwc = new HWComposer(this, *static_cast<HWComposer::E ventHandler *>(this));
   
7. 
   
8.     EGLint format = mHwc–>getVisualID();
   
9.     mEGLConfig = selectEGLConfig(mEGLDisplay, format);
   
10.     mEGLContext = createGLContext(mEGLDisplay, mEGLConfig);
    
11. 
    
12. 
    
13.     for (size_t i=0 ; i<DisplayDevice::NUM_DISPLAY_TYPES ; i++) {
    
14.         DisplayDevice::DisplayType type((DisplayDevice::DisplayType)i);
    
15.         mDefaultDisplays[i] = new BBinder();
    
16.         wp<IBinder> token = mDefaultDisplays[i];
17. 
    
18.         if (mHwc–>isConnected(i) || type==DisplayDevice::DISPLAY_PRIMARY) {
19.             bool isSecure = true;
    
20.             mCurrentState.dis plays.add(token, DisplayDeviceState(type));
    
21.             sp<FramebufferSurface> fbs = new FramebufferSurface(*mHwc< span style="word-wrap:break-word; color:rgb(0,0,204)">, i);
    
22.             sp<SurfaceTextureClient> stc = new SurfaceTextureClient(static_cast< sp<ISurfaceTexture> >(fbs–>getBufferQueue()));
    
23.             sp<DisplayDevice> hw = new DisplayDevice(this, type, isSecure, token, stc, fbs, mEGLConfig);
    
24.             if (i > DisplayDevice::DISPLAY_PRIMARY)
    
25.                 hw–>acquireScreen();            
    
26.             mDisplays.add(token, hw);
    
27.         }
    
28.     }
    
29.     sp<const DisplayDevice> hw(getDefaultDisplayDevice());
    
30. 
    
31.     DisplayDevice::makeCurrent(mEGLDisplay, hw, mEGLContext);
    
32.     initializeGL(mEGLDisplay);
    
33. 
    
34.     mEventThread = new EventThread(this);
    
35.     mEventQueue.setEventThread(mEventThread);
    
36. 
    
37.     mDrawingState = mCurrentState;
38. 
    
39.     mReadyToRunBarrier.open();
40. 
    
41.     initializeDisplays();
42. 
    
43.     startBootAnim();
    
44. 
    
45.     return NO_ERROR;
    
46. }

1. DisplayDevice::DisplayDevice(const sp<SurfaceFlinger>& flinger, …)
   
2. {
   
3.     init(config);
4.     mDisplayDispatcher = new DisplayDispatcher(mFlinger); //新建一个DisplayDispatcher
   
5. }