EXA for radeon experimental patch

[Alan Cox]

On Iau, 2005-09-01 at 09:16 +0200, Lars Knoll wrote:
> What about writes from GPU to PCI? Maybe these exist.

Quite a few cards can do this. It is one reason things like VIA drivers
have command filters for DRI - to stop people blitting patches into the
kernel memory.

In addition almost any AGP card can copy from video memory to AGP. You
then pull the pages out of the GART (fast), cache them (fast), use them
(fast), flush them to ram (not too slow), and put them uncached back
into the GART.