From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752542AbXLFMir (ORCPT ); Thu, 6 Dec 2007 07:38:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752304AbXLFMij (ORCPT ); Thu, 6 Dec 2007 07:38:39 -0500 Received: from hp3.statik.tu-cottbus.de ([141.43.120.68]:38497 "EHLO hp3.statik.tu-cottbus.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751160AbXLFMij (ORCPT ); Thu, 6 Dec 2007 07:38:39 -0500 Message-ID: <4757ED3B.1000703@s5r6.in-berlin.de> Date: Thu, 06 Dec 2007 13:38:19 +0100 From: Stefan Richter User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8.1.11) Gecko/20071128 SeaMonkey/1.1.7 MIME-Version: 1.0 To: Adrian Bunk CC: "Jaursch, Bill" , linux-kernel@vger.kernel.org Subject: Re: FW: Guidance on resources for User Space Device Drivers on 2.6 kernel References: <32A49E5BEBD67A4F877032926EFAA4D209283BD7@ms08.mse3.exchange.ms> <20071206114912.GL15974@stusta.de> In-Reply-To: <20071206114912.GL15974@stusta.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Adrian Bunk wrote: > On Wed, Dec 05, 2007 at 01:29:23AM -0500, Jaursch, Bill wrote: >> I have am in the process of writing a driver that is software only. >> I would like to avoid the caveats of a kernel mode installable module. >>... > > What is "a driver that is software only" > (all kernel code is also software only...)? > > You must describe what you want to do for people being able to actually > help you. Although "software only" is a wrong term here, it's certainly clear from context what he meant. However, what's missing is information about the kind of device he plans to support. Is it a USB device or is it sitting behind a similar bus? Or is it a device on a local bus like PCI? In the latter case, is DMA involved? >> I found FUSD (http://svn.xiph.org/trunk/fusd/), but would like to know >> if this is a stable project. This question should be directed to the authors or maintainers of FUSD. Note, AFAIU from its documentation, FUSD is not a means to implement arbitrary kinds of device drivers in userspace. It allows for "proxying *device file* callbacks into user-space, allowing *device files* to be implemented by" userspace programs (emphasis is mine). I.e. FUSD gives userspace programs only the ability to supply a character special file to other userspace programs. In order to drive real hardware, the FUSD client would additionally need to access other userspace interfaces of the kernel, provided by actual kernelspace drivers. -- Stefan Richter -=====-=-=== ==-- --==- http://arcgraph.de/sr/