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

From: David S. Miller <davem_at_redhat.com>
Date: 2003-05-16 06:07:39
   From: Colin Ngam <cngam@sgi.com>
   Date: Thu, 15 May 2003 08:17:58 -0500
   
   Anyway, to make a long story short, we like to "extend" these
   interfaces to return DMA addresses of 64 bits if and when the
   driver has the full capabality to support DAC - via it's
   DMA mask capability setting.

All devices I am aware of do not support 64-bit addresses for their
descriptors, only 32-bit.

There is a huge difference between using a "64-bit address" and
requiring to generate a DAC cycle, the latter of which is
probably what you need and that is independant of what kind of
address pci_alloc_consistent() is giving you.
Received on Thu May 15 13:11:19 2003

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