From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Date: Fri, 16 May 2003 00:59:23 +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 From: Colin Ngam Date: Thu, 15 May 2003 19:36:55 -0500 I do not believe it is within spec to perform DAC when the Upper 32bits are 0s. That is an illogical requirement in that it means PCI-X mode is illegal in the presence of such addresses. It means that PCI-X devices cannot work in x86 systems with <4GB of memory which is obviously not true.