The utility you're talking about I think is "driconf". It generates a .drirc file in ~. I already adjusted the parameter "vblank_mode" from 0 to 1 as suggested on the 'net. Did not help. I'm still under the impression that the 'radeon' driver does not support vsync with GL.
No announcement yet.
Open source "Radeon" driver: vsync, vblank_mode, tearing and (open)GL