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

David S. Miller
2001-06-28T21:47:06Z

MEHTA,HIREN (A-SanJose,ex1) writes:
> Then why do we have 64-bit dma_addr_t on ia64 ?

Because what the ia64 folks wanted to happen was to make the existing
pci DMA interfaces return 64-bit DAC addresses if the driver made a
certain call into the PCI subsystem first.

I am totally against this architecture, but this is no matter.

If you do nothing other than call the existing PCI dma interfaces, no
matter how things work in the future you will get 32-bit addresses.

Later,
David S. Miller
davem@redhat.com