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

Jes Sorensen (jes@sunsite.dk)
29 Jun 2001 00:20:03 +0200


>>>>> "David" == David S Miller <davem@redhat.com> writes:

David> Jes Sorensen writes:
>> 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.

David> Please note that this is nonstandard and undocumented behavior.

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

Well please also note there has been requests for proper 64 bit DMA
support for over 3 years or so by now.

The interface we use works well, so why should it be changed for other
architecures? Instead it would make a lot more sense to support it on
other architectures that can do 64 bit DMA.

Jes
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