[Linux-ia64] Re: 64 Bits DMA Addresses for Alloc Consistent Interfaces.

From: David Mosberger <davidm_at_napali.hpl.hp.com>
Date: 2003-05-16 01:06:04
>>>>> On Thu, 15 May 2003 08:17:58 -0500, Colin Ngam <cngam@sgi.com> said:

  Colin> Anyway, to make a long story short, we like to "extend" these
  Colin> interfaces to return DMA addresses of 64 bits if and when the
  Colin> driver has the full capabality to support DAC - via it's DMA
  Colin> mask capability setting.

  Colin> This extention will not break current usages of these
  Colin> interface, and as driver changes, this extension will enable
  Colin> platforms to support all of it's Physical Memory via the
  Colin> above 2 Interfaces without exhausting limited system mapping
  Colin> resources.

James and I have been discussing this very point for the last week or
so.  My preferred solution is to add an explicit dma-mask argument to
coherent/non-coherent allocators, but James prefers to do this via a
new GFP flag (GFP_DMA32 or some such).

	--david
Received on Thu May 15 08:08:12 2003

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