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

David S. Miller
2003-05-15T23:53:30Z

From: Colin Ngam <cngam@sgi.com>
Date: Thu, 15 May 2003 18:32:31 -0500

I do not understand what you are saying .. how would a consistent_dma_mask
attribute in the device struct helps pci_alloc_consistent() to return a dma
hanlde that can have the Upper 32 Bits Non 0's, and, moreover,
these Upper 32 Bits are not constants, but can vary greatly, and is
part of the 64 bit Physical System Memory Address?

The mask says that the consistent address "can" have the upper
32-bits non-zero. Then you define a consistent_dma_attrs bitmask
that can define things like "requires >4GB address" etc.

Again, all of this is device attribute stuff and not an issue
concerning the DMA api calls.

But I am ever further confused, how do things like tg3 cards even
function TODAY on any PCI-X systems.