On Thu, Jun 23, 2011 at 06:36:31AM -0700, Matt Thomas wrote: > > That doesn't seem like it can really be right. There are plenty of > > systems where devices cannot DMA from user addresses. > > Really? That seems unlikely.
It's not that devices can't DMA from user addresses; it's that they might or might not be able to DMA from an arbitrary user buffer depending on where it happens to have been placed in the machine's physical address space. -- David A. Holland dholl...@netbsd.org