Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 5 Mar 2002 20:16:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 5 Mar 2002 20:15:48 -0500 Received: from pizda.ninka.net ([216.101.162.242]:41604 "EHLO pizda.ninka.net") by vger.kernel.org with ESMTP id ; Tue, 5 Mar 2002 20:15:47 -0500 Date: Tue, 05 Mar 2002 17:13:33 -0800 (PST) Message-Id: <20020305.171333.72710637.davem@redhat.com> To: adam@yggdrasil.com Cc: sp@scali.com, linux-kernel@vger.kernel.org Subject: Re: Does kmalloc always return address below 4GB? From: "David S. Miller" In-Reply-To: <200203051708.JAA05742@adam.yggdrasil.com> In-Reply-To: <200203051708.JAA05742@adam.yggdrasil.com> X-Mailer: Mew version 2.1 on Emacs 21.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: "Adam J. Richter" Date: Tue, 5 Mar 2002 09:08:20 -0800 Steffen Persvold writes: >I know pci_map_single (and _sg) will >use bounce buffers on platforms without an IOMMU [...] For a moment I thought that must be the point that I was missing, but I don't see any such bounce buffer support in linux-2.5.6-pre2/include/asm-i386/pci.h or arch/i386/kernel/pci-dma.c. I do not see how this is currently implemented on x86 systems with >4GB of RAM. You won't get HIGHMEM pages in your driver unless you are using 2.5.x and tell the scsi layer you are capable to DMA to/from HIGHMEM pages. Similarly for networking drivers, and setting NETIF_F_HIGHDMA in the net device feature flags. - 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/