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

David S. Miller
2001-06-28T22:01:56Z

Jes Sorensen writes:
> >>>>> "Hiren" == MEHTA,HIREN (A-SanJose,ex1) <hiren_mehta@agilent.com> writes:
>
> Hiren> Then why do we have 64-bit dma_addr_t on ia64 ? -hiren
>
> Because on ia64 you will get back a 64 bit pointer if you use
> pci_set_dma_mask() to set a 64 bit mask before calling the pci
> functions in question.

Please note that this is nonstandard and undocumented behavior.

This is not a supported API at all, and the way 64-bit DMA will
eventually be done across all platforms is likely to be different.

Later,
David S. Miller
davem@redhat.com