Messages in this thread |  | | Date | Tue, 22 May 2001 14:34:35 -0700 | From | Jonathan Lundell <> | Subject | Re: alpha iommu fixes |
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At 10:24 PM +0100 2001-05-22, Alan Cox wrote: > > On the main board, and not just the old ones. These days it's >> typically in the chipset's south bridge. "Third-party DMA" is >> sometimes called "fly-by DMA". The ISA card is a slave, as is memory, >> and the DMA chip reads from one ands writes to the other. > >There is also another mode which will give the Alpha kittens I suspect. A >few PCI cards do SB emulation by snooping the PCI bus. So the kernel writes >to the ISA DMA controller which does a pointless ISA transfer and the PCI >card sniffs the DMA controller setup (as it goes to pci, then when nobody >claims it on to the isa bridge) then does bus mastering DMA of its own to fake >the ISA dma
That's sick. -- /Jonathan Lundell. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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