From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60658C3A59F for ; Mon, 19 Aug 2019 09:33:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3FB132087E for ; Mon, 19 Aug 2019 09:33:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727148AbfHSJdW (ORCPT ); Mon, 19 Aug 2019 05:33:22 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:41410 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726491AbfHSJdW (ORCPT ); Mon, 19 Aug 2019 05:33:22 -0400 Received: from 79.184.254.79.ipv4.supernova.orange.pl (79.184.254.79) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.275) id 9d45e80d828adeac; Mon, 19 Aug 2019 11:33:19 +0200 From: "Rafael J. Wysocki" To: Stephen Boyd Cc: "Rafael J. Wysocki" , Tri Vo , Tony Lindgren , Qian Cai , Dmitry Torokhov , Peter Zijlstra , Greg Kroah-Hartman , Linux PM , LKML Subject: Re: "PM / wakeup: Show wakeup sources stats in sysfs" causes boot warnings Date: Mon, 19 Aug 2019 11:33:19 +0200 Message-ID: <1682360.syUnOcd5pY@kreacher> In-Reply-To: <5d56bb77.1c69fb81.58e9d.1f86@mx.google.com> References: <1565731976.8572.16.camel@lca.pw> <5d56bb77.1c69fb81.58e9d.1f86@mx.google.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, August 16, 2019 4:19:35 PM CEST Stephen Boyd wrote: > Quoting Rafael J. Wysocki (2019-08-16 05:17:23) > > On Wed, Aug 14, 2019 at 8:37 PM Tri Vo wrote: > > > > > > On Wed, Aug 14, 2019 at 1:40 AM Tony Lindgren wrote: > > > > > > > > * Stephen Boyd [691231 23:00]: > > > > > I also notice that device_set_wakeup_capable() has a check to see if the > > > > > device is registered yet and it skips creating sysfs entries for the > > > > > device if it isn't created in sysfs yet. Why? Just so it can be called > > > > > before the device is created? I guess the same logic is handled by > > > > > dpm_sysfs_add() if the device is registered after calling > > > > > device_set_wakeup_*(). > > > > > > > > Hmm just guessing.. It's maybe because drivers can enable and disable > > > > the wakeup capability at any point for example like driver/net drivers > > > > do based on WOL etc? > > > > > > > > > There's two approaches I see: > > > > > > > > > > 1) Do a similar check for device_set_wakeup_enable() and skip > > > > > adding the wakeup class until dpm_sysfs_add(). > > > > > > > > > > 2) Find each case where this happens and only call wakeup APIs > > > > > on the device after the device is added. > > > > > > > > > > I guess it's better to let devices have wakeup modified on them before > > > > > they're registered with the device core? > > > > > > > > I think we should at least initially handle case #1 above as multiple > > > > places otherwise seem to break. Then maybe we could add a warning to > > > > help fix all the #2 cases if needed? > > > > > > Makes sense. For case#1, we could also just register the wakeup source > > > without specifying the parent device if the latter hasn't been > > > registered yet. Userspace won't be able to associate a wakeup source > > > to the parent device. But I think it's a reasonable fix, assuming we > > > want to fix devices not being added before calling wakeup APIs #2. > > > > Well, OK > > > > I'm going to drop the entire series from linux-next at this point and > > let's start over. > > I was going to send the first patch I floated as a more formal patch to > be applied to the PM tree. I was waiting to see if the semantics of > device_set_wakeup_*() could be clarified because I don't understand if > they're allowed to be called before device_add(). > > > > > Also note that all of this is not an issue until we start to add > > children under the device passed to device_set_wakeup_enable() and > > friends so maybe that is not a good idea after all? > > My primary goal is to know what wakeup is associated with a device. If > we delay creation of the sysfs node to the time that device_add() is > called then it will allow device_set_wakeup_enable() to be called before > the device is published to userspace. Is anything wrong with that? This > seems to be the intention of the API based on the way > device_set_wakeup_capable() is written. Furthermore, if we make this > change then we don't need to fix various drivers to reorder calls to > device_set_wakeup_enable() and device_add(), so it looks like the right > approach. Sounds reasonable.