Re: (reposting) how to get DMA'able memory within 4GB on 64-bit m achi ne

[David S. Miller]

Jes Sorensen writes:
 > Thats easy
 ...
 > This way you automatically get support for the situation Ben mentioned
 > as well, when doing large allocs and the IOMMU is full you return a
 > full 64 bit address.

And when the IOMMU is "full" what happens to all the SAC only
cards in the machine?  pci_map_{single,sg}() are not allowed
to fail.

See, it's not so easy.

Later,
David S. Miller
[e-mail]