From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 2 Jul 2001 04:24:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 2 Jul 2001 04:24:15 -0400 Received: from fe030.worldonline.dk ([212.54.64.197]:28172 "HELO fe030.worldonline.dk") by vger.kernel.org with SMTP id ; Mon, 2 Jul 2001 04:24:03 -0400 Date: Mon, 2 Jul 2001 10:09:36 +0200 From: Jens Axboe To: Ben LaHaise Cc: "David S. Miller" , Jes Sorensen , "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 Message-ID: <20010702100936.C600@suse.de> In-Reply-To: <15163.43319.82354.562310@pizda.ninka.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 28 2001, Ben LaHaise wrote: > On Thu, 28 Jun 2001, David S. Miller wrote: > > > Please note that this is nonstandard and undocumented behavior. > > > > This is not a supported API at all, and the way 64-bit DMA will > > eventually be done across all platforms is likely to be different. > > Well, what is the standard API to use? All these 64 bit cards in my > machine really make that 95% cpu usage in bounce buffer copying rather > depressing. The current sg list and single mapping functions are useless on 64-bit (and highmem) anyway. I've used struct sg_list as a scatterlist replacement for some time that holds a page/offset/length thing instead, and also used pci_map_page for single mappings. Using a virtual address for this stuff seems a bit short-sighted to me... -- Jens Axboe