From mboxrd@z Thu Jan  1 00:00:00 1970
From: "David S. Miller" <davem@redhat.com>
Date: Fri, 16 May 2003 00:17:20 +0000
Subject: [Linux-ia64] Re: 64 Bits DMA Addresses for Alloc Consistent Interfaces.
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To: linux-ia64@vger.kernel.org

   From: Colin Ngam <cngam@sgi.com>
   Date: Thu, 15 May 2003 18:57:09 -0500
   
   It is in the PCI-X Spec that all PCI-X devices in PCI-X Mode have
   to support DAC.

Having to support DAC cycles does not mean that it must support full
64-bit DMA addresses in it's descriptors.

A cost sensitive PCI-X device may wish to use 32-bit addressing in
it's descriptors in order to keep pin counts down etc.