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

From: David S. Miller <davem_at_redhat.com>
Date: 2003-05-16 10:06:03
   From: Colin Ngam <cngam@sgi.com>
   Date: Thu, 15 May 2003 18:45:42 -0500

   Something else I do not understand .. in the PCI world, what does
   Physical Memory Address got to do with 32Bit Mapped DMA
   Bus Address?
Many platforms direct map, that is what I assumed was happening
here and causing the problems.

   I have not seen any of the drivers broken yet - e.g. qlXXX, acenic,
   tg3 etc.
It only works because these devices happen to allow >32-bit DMA
addresses for descriptors.  You will find eventually that many
comodity pieces of PCI-X hardware will opt to only support 32-bit
DMA addressing for descriptor tables and whatnot.
Received on Thu May 15 17:09:00 2003

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