X Video, XvPutVideo: ATI Radeon M7 Bus Mastering corrupts video capture buffer

[John Klingler]

When using M7 bus mastering to DMA data from the video capture buffer 
the data gets corrupted, developing severe motion artifacts.

I verified that the problem is at the source by setting the M7's overlay 
buffer to coincide with the capture buffer. There is no problem until 
you start the DMA.

I did not have this problem with the ATI M3. The ATI M7 driver for 
Windows also does not have this problem. The bus mastering code I use is 
the same so the problem appears to be elsewhere, probably in the 
initialization.

Does anyone have some experience with, or insight into this?

John Klingler