Change The VGA Resolution On The Fly

Hi, all.

I've encountered a problem while changing the resolution on PPC platform.

In my situation, the graphic card and frame buffer settings are handled by a main application.
The Qt embedded program (GUI) cooperates with the main application by connecting to the same socket IPC.
While the main application changes the VGA resolution, the frame buffer size and resolution will be modified.
Then the Qt GUI will become very strange and need to be restart to run normal in such resolution.

Is there any way to make sure Qt runs normally while the VGA resolution changed on the fly?
It seems I should do something in Qt GUI after the frame buffer settings changed, but I can't find any in the Qt embedded source code.

Thanks for replying.