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.
(specifically the most recent place I've seen that error with was r6xx/r7xx before agd5f implemented interrupts)
ps. Dammit for the edit limit. This seems to be a problem with earlier chips, never mind that before. (Xpress 200M integrated graphics card)
I really have no idea if interrupts should work with your setup or not.
@nanonyme Thank you for your reply. I agree with you: I should move this question to the Open Drivers section. Unfortunately I don't know how to do this.
About the remark about old DRM support. Does anybody know if this has been fixed (or ever will be)? And if so, in which 'radeon' driver version has it been fixed and how do I check my driver version.