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

From: James Bottomley <James.Bottomley_at_HansenPartnership.com>
Date: 2003-05-16 09:24:21
On Thu, 2003-05-15 at 17:44, Colin Ngam wrote:
> However, in PCI-X mode, we do not have the capability to generate SAC addresses.
> And yes, you are also correct that it is very much efficient on our architecture
> to generate DAC for all(PCI/PCI-X)
> 
> So, it is a hard requirement to have DAC for PCI-X devices and not PCI devices.
> 
> Hope that is clear ..

Actually, no.  This seems to imply that your PCI-X cards can *never*
access the first 4GB of memory (because they can't use an IOMMU and they
have to generate a DAC cycle with non zero in bits 63--32).

James
Received on Thu May 15 16:29:16 2003

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