Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750999AbXAOQgk (ORCPT ); Mon, 15 Jan 2007 11:36:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750993AbXAOQgk (ORCPT ); Mon, 15 Jan 2007 11:36:40 -0500 Received: from firewall.rowland.harvard.edu ([140.247.233.35]:39709 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S1750981AbXAOQgj (ORCPT ); Mon, 15 Jan 2007 11:36:39 -0500 Date: Mon, 15 Jan 2007 11:36:38 -0500 (EST) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: Oliver Neukum cc: linux-usb-devel@lists.sourceforge.net, Oliver Neukum , , Subject: Re: [linux-usb-devel] 2.6.20-rc4: usb somehow broken In-Reply-To: <200701151724.42831.oneukum@suse.de> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1810 Lines: 41 On Mon, 15 Jan 2007, Oliver Neukum wrote: > Am Montag, 15. Januar 2007 17:03 schrieb Alan Stern: > > On Mon, 15 Jan 2007, Oliver Neukum wrote: > > > > Upon further thought, a module parameter won't do as the problem > > > will arise without a driver loaded. A sysfs parameter turns the whole > > > affair into a race condition. Will you set the guard parameter before the > > > autosuspend logic strikes? > > > Unfortunately this leaves only the least attractive solution. > > > > There could be a mixed approach: a builtin blacklist that is extensible > > via a procfs- or sysfs-based interface. > > If you want to ask with a lot of bug reports which blacklist was loaded, > then we could. This is a "damned-if-you-do, damned-if-you-don't" situation. Anyway, I've never liked the idea of loading up the kernel with a bunch of preset blacklist entries. For most users that are a waste of space, and unneeded entries almost never get removed. > > Note that we actually have two problems to contend with. Some devices > > must never be autosuspended at all (they disconnect when resuming), and > > others need a reset after resuming. > > Do those who can be brought back with a reset need to be listed at all? > Error handling is not a bad idea. The problem is that the system can't always tell that a reset is needed. There might be no symptoms at all. For example, I've got a USB keypad which doesn't work right after a resume -- key presses never get sent to the computer. As far as the system can tell the device is fine, though. Alan Stern - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/