This is the same issue as in the ati driver, and the same patch applies:
At least accalerated RepeatPad would be great, basically I think its even more
important RepeatNone (if that wouldn't be default).
Mozilla is evaluating using RepeatPad for their images, and my Java2D XRender
backend uses it a lot too heavily.
This is fixed also in radeonhd now.
However, while radeon also accelerate the repeat modes radeonhd still fall back to software.