David Woodhouse <dwmw2 at infradead.org> writes: > On Thu, 2010-07-29 at 21:41 -0700, Eric W. Biederman wrote: >> There isn't a bus master shut off at the core level. > > Effectively, there is if you have an IOMMU. Depends on the IOMMU. There are several dinky IOMMUs that when you shut them off DMA simply goes around them, and is not stopped. Eric