@tjaoz
I am curious. You seem determined that motherboard DMA is working for mediator4000. Could you provide us with a list of which products compatible with the mediator4000 use DMA to access the motherboard resources and some known examples where the feature gives a clear performance advantage over other solutions?
Presumably, DMA'ing to the motherboard memory is only useful for systems that have it. How does the feature help on systems that have local memory on accelerator cards?
Even if PCI -> motherboard memory DMA works, if you have an accelerator card in your system, the chances are you will end up having to use the CPU to shunt data between the local memory and the motherboard area accessible to the PCI.