From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 4 Sep 2001 16:15:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 4 Sep 2001 16:14:56 -0400 Received: from gnu.in-berlin.de ([192.109.42.4]:38660 "EHLO gnu.in-berlin.de") by vger.kernel.org with ESMTP id ; Tue, 4 Sep 2001 16:14:47 -0400 X-Envelope-From: news@bytesex.org To: linux-kernel@vger.kernel.org Path: not-for-mail From: Gerd Knorr Newsgroups: lists.linux.kernel Subject: Re: DMA to/from user buffers Date: 4 Sep 2001 19:30:49 GMT Organization: SuSE Labs, =?ISO-8859-1?Q?Au=DFenstelle?= Berlin Message-ID: In-Reply-To: <20010904164509.A27144@csr-pc1.zib.de> NNTP-Posting-Host: localhost X-Trace: bytesex.org 999631849 8560 127.0.0.1 (4 Sep 2001 19:30:49 GMT) User-Agent: slrn/0.9.7.1 (Linux) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Sebastian Heidl wrote: > > Hi, > > two questions about using an user-supplied buffer (e.g. malloced > in user space) for DMA transfers: > > 1. Is it possible ? > 2. What restrictions/requirements apply for the buffer (alignment...) ? > > Documentation/DMA-mapping.txt only talks about buffers allocated in > kernel space. Lock down the user pages using kiobufs (see include/linux/iobufs.h), then feed these pages to the pci_* functions. Gerd -- Damn lot people confuse usability and eye-candy.