Re: alpha iommu fixes

David S. Miller (davem@redhat.com)
Sun, 20 May 2001 23:53:42 -0700 (PDT)


Andrea Arcangeli writes:
> Assume I have a dozen of PCI cards that does DMA using SG tables that
> can map up to some houndred mbytes of ram each, so I can just program
> the cards to start the dma on those houndred mbyte of ram, most of the
> time the I/O is not simulaneous, but very rarely it happens to be
> simultaneous and in turn it tries to pci_map_sg more than 4G of physical
> ram.

What are these "devices", and what drivers "just program the cards to
start the dma on those hundred mbyte of ram"?

Are we designing Linux for hypothetical systems with hypothetical
devices and drivers, or for the real world?

Later,
David S. Miller
davem@redhat.com
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