Problem: Wait for VSync on pipe A and Wake up on pipe B

[Nicolas Cadio]

Hello,

I have an application which must to synchronize with the vertical synchronisation of my display.
To do this synchronization, I use a function of GLX (glXWaitVideoSyncSGI).

This function call the function DRM to wait the vertical synchronization (drmWaitVBlank) and the driver (drm.ko) does a wait on the pipe A of my Xserver.

But my output (LVDS) of my Xserver is connected to the pipe B and so the driver (drm.ko) does a wake up on the pipe B.

So my applicaton is not synchronized with my display.

I would like to know how to configure my application for it uses the pipe B when it does a wait for the vertical synchronization.
Where I can configure my application for it uses the pipe B for the VSync ?
Is it in the xorg.conf or elsewhere?

Thanks, Nicolas