https://bugs.freedesktop.org/show_bug.cgi?id=79223
--- Comment #13 from Michel Dänzer michel@daenzer.net --- (In reply to comment #9)
No effect I'm afraid. Since this is a full screen application I assume it was already using flipping and not blitting anyway?
Probably. For the sake of testing, have you tried disabling page flipping in addition to SwapBuffersWait?
(In reply to comment #12)
Down to dri2_drawable_get_buffers() now. I assume I'll be hitting a point where I'll have to switch over to looking in the X server soon...
Yep, it's waiting for DRI2 buffer information from the X server, which is delayed until the previous buffer swap actually finishes.
FWIW, you might get somewhat less confusing timings if you call glFinish() before glXSwapBuffers().