From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966438AbWKNW5U (ORCPT ); Tue, 14 Nov 2006 17:57:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S966439AbWKNW5U (ORCPT ); Tue, 14 Nov 2006 17:57:20 -0500 Received: from smtp105.sbc.mail.mud.yahoo.com ([68.142.198.204]:39558 "HELO smtp105.sbc.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S966438AbWKNW45 (ORCPT ); Tue, 14 Nov 2006 17:56:57 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=awyeROSp7AiFviPX7HzbIB/8hixIF6xMA2lKRb1DtdK718NbqaSUJj835yszLiB7InXad2qjYJIHOmwoQ3r/G0idQ7HL/8mizZ5wNHzkx+egj7/g2JLU3cQNqO+DWWQ8MwkiHX7kJ91g7gDKfisL5ZsFVCq0u+uc1z1wg5pm6yk= ; X-YMail-OSG: dPTgA7QVM1nBh6p_JBrMB9Ag1D7yrpRzo4cc3jQTYHwk2GWTW9BxgFR0O8iYAYiWoQLIiCtP5ZePGfiJYiW9wB06mGP.Ov4bcwqIGi28nqQtoVbbFquCgN.4sE8hTosRMLp8LE_1vY1jikcCY_tANXutxYJ9sn2OZe4- From: David Brownell To: Alan Stern Subject: Re: [linux-usb-devel] 2.6.19-rc5 regression: can't disable OHCI wakeup via sysfs Date: Tue, 14 Nov 2006 14:56:51 -0800 User-Agent: KMail/1.7.1 Cc: arvidjaar@mail.ru, linux-usb-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200611141456.52201.david-b@pacbell.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 14 November 2006 1:42 pm, Alan Stern wrote: > On Tue, 14 Nov 2006, David Brownell wrote: > > > On Monday 13 November 2006 9:15 am, Alan Stern wrote: > > > On Mon, 13 Nov 2006, David Brownell wrote: > > > > > > > It's a *driver model* API, which is also accessible from sysfs ... to support > > > > per-device policies, for example the (a) workaround. The mechanism exists > > > > even on kernels that don't include sysfs ... although on such systems, there > > > > is no way for users to do things like say "ignore the fact that this mouse > > > > claims to issue wakeup events, its descriptors lie". > > > > > > Yes, it is separate from sysfs -- but it is _tied_ to the sysfs API. > > > > I can't agree. If you deconfigure sysfs, it still works. > > Since it's independent like that, there's no way it's "tied". > > We could carry on this argument indefinitely. Yes, the device_may_wakeup > stuff does work without sysfs. But it doesn't do anything significant; it > amounts to no more than device_can_wakeup(). AFAIK there's no way to > change the setting of the may_wakeup flag other than via sysfs. That's > what I meant by "tied". So "tied" means "nobody has yet needed to create a different API for that subset of the mechanism"? Still can't agree. Nothing's preventing anyone from creating such an API, if they need to. > > So "may" is correct, and "can" is insufficient. > > Things work differently in uhci-hcd. They shouldn't. That's the point of having this in the driver model: so that all wakeup-capable devices can/will act the same in terms of the basic capability and policy. (Of course, there are ugly PPC/OF-only enumeration issues that keep us from kicking in the wakeup mechanisms for PCI devices. But that's a separate issue, specific to PCI ... although it sucks hugely, since so few developers have non-PCI wakeup-capable devices.) > However even when it is added and may_wakeup is off, autostop will still > function. It won't rely on interrupts or other wakeup events, though -- > instead the root-hub status polling mechanism will be used. Well, as was said previously: For UHCI it's not "just" a PM mechanism. - Dave