How to utilize the DSS subsystem of OMAP 3530 in Qt application

Hi,

We are now developing an application using the Qt for Embedded Linux targeting the OMAP 3530 platform. We know that OMAP 3530 has DSS subsystem for video and graphics overlay. It has one plane for graphics and two plane for video. But we don't know how to use this feature in Qt. We want to render some OpenGL scene to the graphics plane and overlay some text and 2D vector using one video plane. So my question is : how to control which plane to render into by using Qt framework? Is Qt aware of the multiple planes provided by OMAP 3530? In addition, Qt's QGLWidget provided the paintGL() and paintOverlayGL() function to render into the main plane and overlay plane. When I construct the QGLWidget with HasOverlay enabled on the OMAP 3530 hardware, the GLFormat's HasOverlay is ture, but HasGLOverlay is false, and the paintOverlayGL() function doesn't work. So everyone knows the difference between HasOverlay and HasGLOverlay? Is there any documentation or example to show how to use the DSS subsystem in Qt Framework?

Thanks.

Mczhao,