Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762188AbXHCMeS (ORCPT ); Fri, 3 Aug 2007 08:34:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761228AbXHCMeJ (ORCPT ); Fri, 3 Aug 2007 08:34:09 -0400 Received: from rv-out-0910.google.com ([209.85.198.187]:27043 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761210AbXHCMeH (ORCPT ); Fri, 3 Aug 2007 08:34:07 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=rX8cWXFMBzNhP0y+mQu3WUfXWdabkaId5Qh12Tewt7fDqRAzWAuNyvrxQSYFVb3IQ0P+X42mKjwj53m5+ShmOIT3yBHu9QQ+C45CJ7+hKiztKb0FV5N1afRBze1YL51WjlzQLyNi4VTgzladHCgmo/7wlYwd/k5/SzQifce9Nl8= Message-ID: <31e679430708030534v5a8f1c9p3eb25c9e3db48f0a@mail.gmail.com> Date: Fri, 3 Aug 2007 08:34:06 -0400 From: "Felipe Balbi" To: "Rogan Dawes" Subject: Re: [linux-usb-devel] [PATCH] USB: Only enable autosuspend by default on certain device classes Cc: "Matthew Garrett" , "Greg KH" , linux-usb-devel@lists.sourceforge.net, "Oliver Neukum" , linux-kernel@vger.kernel.org, "David Brownell" , "Alan Stern" In-Reply-To: <46B31F03.80908@dawes.za.net> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200708022301.08719.david-b@pacbell.net> <20070803112824.GA16802@srcf.ucam.org> <200708031344.03282.oliver@neukum.org> <20070803120418.GB16802@srcf.ucam.org> <46B31F03.80908@dawes.za.net> X-Google-Sender-Auth: 780bf1c3f16bde31 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2684 Lines: 68 On 8/3/07, Rogan Dawes wrote: > Matthew Garrett wrote: > > On Fri, Aug 03, 2007 at 01:44:02PM +0200, Oliver Neukum wrote: > >> Am Freitag 03 August 2007 schrieb Matthew Garrett: > >>> It's certainly possible to do that, but it's also possible to have a > >>> userspace solution that whitelists devices. The question is whether the > >>> default kernel behaviour should be "Save power, but potentially break > >>> some of my devices" or "Don't break my devices, but use some more > >>> powre". > >> If both options have drawbacks, IMHO we follow the standard, which > >> says that devices must support suspension. > > > > Except that lots of hardware doesn't follow the standard in this > > respect, otherwise we wouldn't be having this discussion. Personally, I > > think "Will break an unknown number of devices" is a significantly > > larger drawback than "Will consume a small quantity of additional > > power". > > > > I guess the question could be phrased: > > Which one is more likely to conclude at some point? > > That is, if we blacklist by default, we consume that additional power > indefinitely, because it is unlikely that people will report "my machine > uses 200mW more than I think it should", and thus we are unlikely to > build up knowledge of exactly which devices/classes should be blacklisted. > > Compare that to: > > "My USB printer broke, guess I'd better report it to LKML". > > The first option is unlikely to ever reach a satisfactory conclusion, > whereas the second one is quite likely to flush out the guilty parties > within a relatively short time. Even though we should be following what the specs says and find other ways of threating the "messy" devices. A sysfs entry for enabling/disabling autosuspend and even to add devices to blacklist seems quite nice to me. > > FWIW. > > Rogan > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > linux-usb-devel@lists.sourceforge.net > To unsubscribe, use the last form field at: > https://lists.sourceforge.net/lists/listinfo/linux-usb-devel > -- Best Regards, Felipe Balbi felipebalbi@users.sourceforge.net - 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/