the same code about show my image and update image code in 2 Environment
1. Desktop x86 ubuntu =>QT lib is 5.1.1
2. embed linux(ubuntu) arm (Beaglebone Black) ==>QT lib 4.8.1

use cross complier QT configure:
./configure -prefix /opt/qt-Arm-ubuntu -embedded arm -platform qws/linux-x86-g++ -xplatform qws/linux-arm-ubuntu -depths 16,24,32 -no-mmx -no-3dnow -no-sse -no-sse2 -no-glib -no-cups -no-largefile -no-accessibility -no-openssl -no-gtkstyle -fast -nomake demos -nomake examples -no-svg -no-phonon -no-qt3support -no-svg -qt-gfx-linuxfb -no-javascript-jit -confirm-license -opensource -no-webkit -little-endian -host-little-endian -qt-kbd-linuxinput -qt-mouse-linuxinput

QGraphicsScene::update work in Desktop x86 ubunt but not work in embed linux(ubuntu) arm



My code :

MainWindow.h

QImage* rawImg;
QGraphicsView *usrView;
QGraphicsScene* scene;
uchar* rawData;
uchar* rawDataTmp ;
int rawW = 400;
int rawH = 400;
int rawW2 = 400;
int rawH2= 200;

MainWindow.cpp

MainWindow::init()
{
rawData =(uchar*) malloc(rawW*rawH*4);
rawDataTmp = rawData;
while(rawDataTmp < (rawData+rawW*rawH*4))
{
*rawDataTmp = 0;
rawDataTmp++;
//g
*rawDataTmp = 0xff;
rawDataTmp++;
//r
*rawDataTmp = 0;
rawDataTmp++;
//a
*rawDataTmp = 0;
rawDataTmp++;
}
rawImg = new QImage(rawData,rawW,rawH,QImage::Format_RGB32);
scene = new QGraphicsScene(this);
scene->addPixmap(QPixmap::fromImage(*rawImg));
usrView = new UsrGV(ui->centralWidget);
usrView->setScene(scene);
usrView->installEventFilter(this);
}

bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
if (event->type() == QEvent::MouseButtonPress )
{
rawDataTmp = rawData ;
while(rawDataTmp < (rawData+rawW2*rawH2*4))
{
//b
*rawDataTmp = 0xff;
rawDataTmp++;
//g
*rawDataTmp = 0;
rawDataTmp++;
//r
*rawDataTmp = 0xff;
rawDataTmp++;
//a
*rawDataTmp = 0;
rawDataTmp++;
}
scene->update();
}
}

when i press mouse, in Desktop x86 ,i can see pink color ,but arm embeded linux only green

does anyone can tell me why?
and how can i refresh graphicsview in embed linux(ubuntu) arm

Ps : i know create new scene and then setScene can refresh the graphicview but not good for me,
my main project need to update image every 100 ms ==> it will cause mouse strange (move very slowly)