So, I've upgraded my desktop box to Fedora 7. I like it a lot. It's mostly a bug fix/refinement release (IMHO), but there's one glaring omission: in order to run the ATI fglrx driver you have to roll back to an older version of xorg.
Not gonna happen.
Anyway, the 3D support for the open source radeon driver is getting there, but I was having trouble getting it sync'ed to vblank. Figured it out, a drirc file is necessary. It can be in /etc, or you can have a .drirc one in your home directory, but that's where you set the setting.
This page from the DRI Wiki shows an example of how to implement the vblank.
glxgears doesn't *seem* to be sync'ing based upon its output, but tearing isn't there anymore (at least not obvious tearing), so I think it works. I'll keep testing.