From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262578AbTDHXfw (for ); Tue, 8 Apr 2003 19:35:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262579AbTDHXfw (for ); Tue, 8 Apr 2003 19:35:52 -0400 Received: from almesberger.net ([63.105.73.239]:10250 "EHLO host.almesberger.net") by vger.kernel.org with ESMTP id S262578AbTDHXfv (for ); Tue, 8 Apr 2003 19:35:51 -0400 Date: Tue, 8 Apr 2003 20:47:21 -0300 From: Werner Almesberger To: David Lang Cc: Roman Zippel , linux-kernel@vger.kernel.org Subject: Re: 64-bit kdev_t - just for playing Message-ID: <20030408204721.H18709@almesberger.net> References: <20030408195305.F19288@almesberger.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ; from david.lang@digitalinsight.com on Tue, Apr 08, 2003 at 04:11:05PM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org David Lang wrote: > the biggest problem I see with dynamic numbers is that it needs a > userspace devfs type solution for creating and maintaining the device > nodes that are then used. Agreed, this is the difficult part. This probably means that the kernel will have to come with a default initrd-like setup that is built and attached by "make bzImage" and the like. I thought that people were quite actively working towards something like this ? > somthing that is hard to get people to agree to (remember the devfs names > that everyone gripes about are not what richard started with it's what he > switched to to get things into the kernel, they changed many times during > that process) Actually, here we may have an advantage now. The "old way" was to write the driver, allocate a number, release the driver, and suggest a device name. If somebody didn't like the name, they could easily change it to something else. Nobody had to agree with the author. devfs was different. The one thing everybody has to agree on is the kernel. And gratuitous differences in "vendor kernels" are frowned upon, and are no less of a pain in individual kernels either. So now everyone had to accept the name the author assigned - or fight with the author until the name changed. (Of course, one could have mounted devfs in some dark corner and set up a link tree pointing to it, which wouldn't have been too different from using sysfs. devfs was never really positioned to take such a role, and seems to carry too much overhead trying to be a "full" /dev replacement to be justifiable as an "almost" /dev replacement.) By completely removing such policy from the kernel, we return to the status quo ante: user-visible names only need to be agreed on during early system bringup. After that, the "device file manager" takes over, and that one can just use a local device name database. - Werner -- _________________________________________________________________________ / Werner Almesberger, Buenos Aires, Argentina wa@almesberger.net / /_http://www.almesberger.net/____________________________________________/