From mboxrd@z Thu Jan 1 00:00:00 1970 From: Colin Ngam Date: Thu, 15 May 2003 23:51:35 +0000 Subject: [Linux-ia64] Re: 64 Bits DMA Addresses for Alloc Consistent Interfaces. Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org "David S. Miller" wrote: > From: Colin Ngam > 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. Hi David, Implementation details aside, you are agreeing that the pci_alloc_consistent() interface can return an address > 4GB and we can document as such? Thanks. colin > > > But I am ever further confused, how do things like tg3 cards even > function TODAY on any PCI-X systems.