(In reply to Michel Dänzer from comment #4)
> Can you get the same or at least similar tearing on Brazos with
> 
>  Option "SwapbuffersWait" "off"

With this option I started to have tearing on Brazos. A bit different than
reported on Kabini: it is present randomly on whole screen.
> 
> or
> 
>  Option "AccelMethod" "glamor"

With this option I started to have tearing on Brazos almost exactly the same
like on Kabini.

> 
> in xorg.conf? If yes, the problem is that page flipping cannot be used for
> the MythTV window, most likely because its dimensions do not match the X11
> screen dimensions.

MythTV works here in full-screen. DI (also 2xHW) works OK on Brazos but not on
Kabini. As enabling GLAMOR on Brazos causes exactly the same DI issue on Brazos
- isn't issue within GLAMOR?