From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 28 Jun 2001 18:20:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 28 Jun 2001 18:20:42 -0400 Received: from smtp1.cern.ch ([137.138.128.38]:33041 "EHLO smtp1.cern.ch") by vger.kernel.org with ESMTP id ; Thu, 28 Jun 2001 18:20:12 -0400 To: "David S. Miller" Cc: "MEHTA,HIREN (A-SanJose,ex1)" , "'linux-kernel@vger.kernel.org'" Subject: Re: (reposting) how to get DMA'able memory within 4GB on 64-bit m achi ne In-Reply-To: <15163.43319.82354.562310@pizda.ninka.net> From: Jes Sorensen Date: 29 Jun 2001 00:20:03 +0200 In-Reply-To: "David S. Miller"'s message of "Thu, 28 Jun 2001 15:01:27 -0700 (PDT)" Message-ID: User-Agent: Gnus/5.070096 (Pterodactyl Gnus v0.96) Emacs/20.4 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >>>>> "David" == David S Miller writes: David> Jes Sorensen writes: >> Because on ia64 you will get back a 64 bit pointer if you use >> pci_set_dma_mask() to set a 64 bit mask before calling the pci >> functions in question. David> Please note that this is nonstandard and undocumented behavior. David> This is not a supported API at all, and the way 64-bit DMA will David> eventually be done across all platforms is likely to be David> different. Well please also note there has been requests for proper 64 bit DMA support for over 3 years or so by now. The interface we use works well, so why should it be changed for other architecures? Instead it would make a lot more sense to support it on other architectures that can do 64 bit DMA. Jes