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标题: void SurfaceFlinger::postFramebuffer() [打印本页]

作者: zangcf 时间: 2016-4-17 11:00
标题: void SurfaceFlinger::postFramebuffer()
void SurfaceFlinger::postFramebuffer()
{
ATRACE_CALL();

const nsecs_t now = systemTime();
mDebugInSwapBuffers = now;

HWComposer& hwc(getHwComposer());
if (hwc.initCheck() == NO_ERROR) {
      if (!hwc.supportsFramebufferTarget()) {
         // EGL spec says:
         // "surface must be bound to the calling thread's current context,
         // for the current rendering API."
         getDefaultDisplayDevice()->makeCurrent(mEGLDisplay, mEGLContext);
      }
      hwc.commit();
}

// make the default display current because the VirtualDisplayDevice code cannot
// deal with dequeueBuffer() being called outside of the composition loop; however
// the code below can call glFlush() which is allowed (and does in some case) call
// dequeueBuffer().
getDefaultDisplayDevice()->makeCurrent(mEGLDisplay, mEGLContext);

for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
      sp<const DisplayDevice> hw(mDisplays[dpy]);
#ifdef MTK_AOSP_ENHANCEMENT
      if (!hw->mustRecompose()) continue;
#endif
      const Vector< sp<Layer> >& currentLayers(hw->getVisibleLayersSortedByZ());
      hw->onSwapBuffersCompleted(hwc);
      const size_t count = currentLayers.size();
      int32_t id = hw->getHwcDisplayId();
      if (id >=0 && hwc.initCheck() == NO_ERROR) {
         HWComposer:

ayerListIterator cur = hwc.begin(id);
const HWComposer:

ayerListIterator end = hwc.end(id);
         for (size_t i = 0; cur != end && i < count; ++i, ++cur) {
            currentLayers[i]->onLayerDisplayed(hw, &*cur);
         }
      } else {
         for (size_t i = 0; i < count; i++) {
            currentLayers[i]->onLayerDisplayed(hw, NULL);
         }
      }
}

mLastSwapBufferTime = systemTime() - now;
mDebugInSwapBuffers = 0;

uint32_t flipCount = getDefaultDisplayDevice()->getPageFlipCount();
if (flipCount % LOG_FRAME_STATS_PERIOD == 0) {
      logFrameStats();
}
}

作者: zangcf 时间: 2016-4-17 11:16
另一方面，HWC合成完毕后，SurfaceFlinger会依次调用DisplayDevice:

nSwapBuffersCompleted() -> FramebufferSurface:

nFrameCommitted()。onFrameCommitted()核心代码如下：
148 sp<Fence> fence = mHwc.getAndResetReleaseFence(mDisplayType);
...
151 status_t err = addReleaseFence(mCurrentBufferSlot,
152 mCurrentBuffer, fence);
此处拿到HWC生成的FramebufferTarget的releaseFence，设到FramebufferSurface中相应的GraphicBuffer Slot中。这样FramebufferSurface对应的GraphicBuffer也可以被释放回BufferQueue了。当将来EGL从中拿到这个buffer时，照例也要先等待这个releaseFence触发才能使用。

作者: zangcf 时间: 2016-4-17 11:17
sp<const DisplayDevice> hw(mDisplays[dpy]);
这个地方是hw的定义

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