Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 6 Jul 2001 07:12:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 6 Jul 2001 07:12:48 -0400 Received: from router-100M.swansea.linux.org.uk ([194.168.151.17]:27921 "EHLO the-village.bc.nu") by vger.kernel.org with ESMTP id ; Fri, 6 Jul 2001 07:12:35 -0400 Subject: Re: DMA memory limitation? To: sp@scali.no (Steffen Persvold) Date: Fri, 6 Jul 2001 12:08:51 +0100 (BST) Cc: helgehaf@idb.hist.no (Helge Hafting), pvvvarma@techmas.hcltech.com (Vasu Varma P V), linux-kernel@vger.kernel.org In-Reply-To: <3B458888.75C50552@scali.no> from "Steffen Persvold" at Jul 06, 2001 11:44:40 AM X-Mailer: ELM [version 2.5 PL3] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: From: Alan Cox Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > A problem arises on 64 bit platforms (such as IA64) if your PCI card is only 32bit (can > address the first 4G) and you don't wan't to use bounce buffers. If you use GFP_DMA on GFP_DMA is ISA dma reachable, Forget the IA64, their setup is weird and should best be ignored until 2.5 as and when they sort it out. > bounce buffers are needed. On Alpha GFP_DMA is not limited at all (I think). Correct me if Alpha has various IOMMU facilities > I'm wrong, but I really think there should be a general way of allocating memory that is > 32bit addressable (something like GFP_32BIT?) so you don't need a lot of #ifdef's in your > code. No ifdefs are needed GFP_DMA - ISA dma reachable pci_alloc_* and friends - PCI usable memory - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/