There is garbage on screen with some stretched XRender pictures with radeon
driver and enabled EXAPixmaps, see for example MSEide without xorg.conf

http://sourceforge.net/projects/mseide-msegui/

MSEgui uses stretched one pixel width or height pixmaps in order to draw linear
color gradients. 

If you add Option "EXAPixmaps" "off" in Section "Device" of xorg.conf display
is OK but performance falls.

Same problem using NOUVEAU driver. I can't figure out how disable EXAPixmaps
for nouveau driver.

Reproducible: Always