From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jes Sorensen Date: Tue, 10 Jul 2001 15:42:02 +0000 Subject: Re: [Linux-ia64] RE: DMA memory limitation? 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 >>>>> "Matt" = Matt Domsch writes: >>> The important thing is that pci_alloc_consistent and the other PCI >>> DMA functions work as advertised on IA64. If you pass NULL to >>> pci_alloc_consistent, IA64 should give you an ISA DMA-able >>> address. If you don't, you get a 32-bit PCI DMA address. Matt> Never have I seen a using NULL pci_dev pointer give you a 64-bit Matt> DMA address. Per Jeff's comment, it should give you an address Matt> with a mask of 24-bits (within ISA space, i.e. <16MB), but since Matt> you can't add in any ISA cards on IA-64, this wouldn't make much Matt> sense either. Well but we don't have any ISA busses on the ia64 boxes. The only reason to return a 24 bit mask would be for broken devices that require a 31 or 29 bit or similar mask, but one should set that via the dma_mask interface anyway. Jes