https://bugs.freedesktop.org/show_bug.cgi?id=29726
--- Comment #7 from Alex Deucher agd5f@yahoo.com 2010-10-24 22:09:03 PDT --- (In reply to comment #6)
I was thinking you actually meant the .drirc setting rather than an actual environment variable but you were right. Setting this in .drirc makes no difference but the environment variable does indeed make the problem go away.
It's works in the .drirc as well, but it requires slightly different handling for dri2 drivers, e.g.,
<driconf> <device screen="0" driver="dri2"> <application name="Default"> <option name="vblank_mode" value="0" /> </application> </device> </driconf>
I quite like vsyncing so I'm a little sad if it's broken. I think it was working before?
It wasn't supported before. KMS vsync support was added with the commit cited in this bug.