Merge "Don't call hwc set() if there is nothing new to do" into ics-mr0

    // post surfaces (if needed)

    handlePageFlip();

    if (mDirtyRegion.isEmpty()) {

        // nothing new to do.

        return true;

    }

    if (UNLIKELY(mHwWorkListDirty)) {

        // build the h/w work list

        handleWorkList();

void SurfaceFlinger::postFramebuffer()

{

    // this should never happen. we do the flip anyways so we don't

    // risk to cause a deadlock with hwc

    LOGW_IF(mSwapRegion.isEmpty(), "mSwapRegion is empty");

    const DisplayHardware& hw(graphicPlane(0).displayHardware());

    const nsecs_t now = systemTime();

    mDebugInSwapBuffers = now;

        // data.

        //

        // Also we want to make sure to not clear areas that belong to

        // layers above that won't redraw (we would just erasing them),

        // layers above that won't redraw (we would just be erasing them),

        // that is, we can't erase anything outside the dirty region.

        Region transparent;

void SurfaceFlinger::repaintEverything() {

    Mutex::Autolock _l(mStateLock);

    const DisplayHardware& hw(graphicPlane(0).displayHardware());

    mDirtyRegion.set(hw.bounds()); // careful that's not thread-safe

    mDirtyRegion.set(hw.bounds());

    signalEvent();

}