Comment 1 for bug 1213801

On the other hand, waiting for all outputs' page flips to complete does avoid tearing. And this bug doesn't occur until the rendering load is high.

I think we need to choose between:
  (a) Sometimes low frame rate (stutter) but never tearing; or
  (b) Always smooth frame rate but tearing on /some/ monitors in clone mode.

I'm really hoping there's an option (c).