From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756382AbZEGXMo (ORCPT ); Thu, 7 May 2009 19:12:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752278AbZEGXMa (ORCPT ); Thu, 7 May 2009 19:12:30 -0400 Received: from mail-fx0-f158.google.com ([209.85.220.158]:34147 "EHLO mail-fx0-f158.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756891AbZEGXM2 convert rfc822-to-8bit (ORCPT ); Thu, 7 May 2009 19:12:28 -0400 MIME-Version: 1.0 In-Reply-To: References: From: Kay Sievers Date: Fri, 8 May 2009 01:12:07 +0200 Message-ID: Subject: Re: usbfs, claiming entire usb devices To: Alan Stern Cc: Kernel development list , Pantelis Koukousoulas , USB list Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 8, 2009 at 00:47, Alan Stern wrote: >> Or is that a specific requirement where things would go wrong when the >> kernel binds to a device first? > > You've got it.  Sometimes devices are in a very precarious state (such > as during a firmware update) and they need to go into a particular > configuration.  Letting the kernel install some random configuration at > such times doesn't work. I see. You mentioned earlier, that you would need to match the holder of the "lock" and the one that accesses the device? Wouldn't it be sufficient already, if you can take a "lock" at the specific port, that prevents the kernel to access the device when it shows up? You thought of supporting a number of different users, with different uids, or would that be a root-only action? Thanks, Kay