https://bugs.freedesktop.org/show_bug.cgi?id=28771
--- Comment #3 from Jesse Barnes jbarnes@virtuousgeek.org 2010-06-28 15:41:03 PDT --- Oh, for the DRI2 radeon driver you'll probably need to add an explicit option somewhere; maybe the code path that used to check the vblank_mode flags is no longer called.
See intel_screen.c: ... DRI_CONF_VBLANK_MODE(DRI_CONF_VBLANK_ALWAYS_SYNC) ...
there's probably a similar section in the radeon driver somewhere. You'll also need to add support for the new DRI2 config extension to the driver, again see intel_screen.c's intelScreenExtensions array: ... &dri2ConfigQueryExtension.base, ...
Hope that helps.