From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 17 Jul 2002 14:13:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 17 Jul 2002 14:13:38 -0400 Received: from zipcon.net ([209.221.136.5]:43435 "HELO zipcon.net") by vger.kernel.org with SMTP id ; Wed, 17 Jul 2002 14:13:37 -0400 Message-ID: <3D35B43A.4050804@tahomatech.com> Date: Wed, 17 Jul 2002 11:15:22 -0700 From: William Waddington User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:0.9.4.1) Gecko/20020508 Netscape6/6.2.3 X-Accept-Language: en-us MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: kiobufs and highmem Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello All, I have a 2.4.x char driver which works fine, except in boxes with lots of memory. user_buffer -> write() -> map_user_kiobuf() -> pci_map_sg() -> Pci DMA I'm using the .page/.offset version of the scatterlist, but in the HIGHMEM case, map_user_kiobuf() seems to return peculiar page addresses. What is the state of kiobufs/HIGHMEM in 2.4.x? Do I need to implement a bounce buffer in the driver? Some email correspondence indicates so, but I would be grateful for a definitive word from the kernel folks. TIA, Bill Waddington -- *** please note our new name and address *** Tahoma Technology (formerly Ikon Corporation) 107 2nd Avenue North, Seattle, WA, USA, 98109 Voice: 206.728.6465 Fax: 206.728.1633 http://www.tahomatech.com tahoma@tahomatech.com