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=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 298E1C433E0 for ; Fri, 12 Feb 2021 03:06:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E7D6564E2A for ; Fri, 12 Feb 2021 03:06:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229887AbhBLDFy (ORCPT ); Thu, 11 Feb 2021 22:05:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229457AbhBLDFp (ORCPT ); Thu, 11 Feb 2021 22:05:45 -0500 Received: from mail-yb1-xb36.google.com (mail-yb1-xb36.google.com [IPv6:2607:f8b0:4864:20::b36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 084CCC061786 for ; Thu, 11 Feb 2021 19:05:04 -0800 (PST) Received: by mail-yb1-xb36.google.com with SMTP id k4so7749516ybp.6 for ; Thu, 11 Feb 2021 19:05:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=umGRLg+1wx6Dct4xi++63waA6bhM8DuWO/MBgfuP+to=; b=lsYcskdEfrp1rxwOSLfMqivVJo7Eb/oCK4ZrFyXldZVxt+imnfC2bhNK2sjF2ipVpu zrz+ZBYcBg8XtdfcB4ufK2WQ+WoHHBIWzPYtmClrGYWKdN5myUty6b5PVtlqHBnkjhHh jn3gUCXdspQAlsvVxDpLat72A9XXVYoqYP1Sq6UvQcSp2JD9pOXbEtpzLQ/5iSs0rNt1 XEHSysOyNIjyhN/usLmg7Mee3yeyEU9qB7SSkCEYwGCtZPQeKKuISp66qKABB/n9rqub OA37bViFiHQm6uBKIRutBZMytB6oZPHDrsdJt3aSTPq7l+adm+bXfmphTKeu5Hzmj14z 6ITw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=umGRLg+1wx6Dct4xi++63waA6bhM8DuWO/MBgfuP+to=; b=EqL1xpaYbqqNLpYYXZfsmIP8D5aE7Rlquts7yVwgaye47+Yladt9ZsWodr1lQGFpda Q0YJIUjCdf93hUAV/J07pCigDFzGVZyyNlzUiL47yULXMXZgGi0o1XYVDEbb3+FZzIkH VHcy6HOPibDN7vYZmLSvVnjrDNe33DWy2UaHdnkDzSvoqHKPB4aIDeQW4RaSpREPwc77 Ux07+tX547avrPawWyyD6FmXRh22Efb8kcyhVd+lsLIN2A90nxpqZdf0xueFaMHZlXqh w41o6rXs0sCNzDk1H7dYWcOQT1VyXd1mp1GNFs3zi09/VkIA6xJpUsvCKsB4fmRUfjQw jaVw== X-Gm-Message-State: AOAM531Cv+4dGVdZTOe+xa/Wf9NrhwwkHUI7SWncVwZ3UEmZ6DD08JBZ 3X+6xlldny1v4Swb2dntvSQ1pDx/75zjpS2NdrKY+1+5Tko= X-Google-Smtp-Source: ABdhPJwbFxKsHdBt5t1veT/tIV3pPie1EclgzZtn0vZznGL3ATsg54MPxKEJCSIDP2nRsDk86HDxpF/SC6W+cofl9Eo= X-Received: by 2002:a25:8b8b:: with SMTP id j11mr1225200ybl.310.1613099103994; Thu, 11 Feb 2021 19:05:03 -0800 (PST) MIME-Version: 1.0 References: <20201218031703.3053753-1-saravanak@google.com> <56f7d032-ba5a-a8c7-23de-2969d98c527e@nvidia.com> <17939709-f6f4-fa9c-836f-9779081c4087@nvidia.com> <6a43e209-1d2d-b10a-4564-0289d54135d3@nvidia.com> In-Reply-To: From: Saravana Kannan Date: Thu, 11 Feb 2021 19:04:28 -0800 Message-ID: Subject: Re: [PATCH v1 0/5] Enable fw_devlink=on by default To: "Rafael J. Wysocki" Cc: Jon Hunter , Greg Kroah-Hartman , Android Kernel Team , LKML , Jisheng Zhang , Kevin Hilman , John Stultz , Nicolas Saenz Julienne , Marc Zyngier , linux-tegra Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 11, 2021 at 9:48 AM Rafael J. Wysocki wrote: > > On Thu, Feb 11, 2021 at 6:15 PM Saravana Kannan wrote: > > > > On Thu, Feb 11, 2021 at 7:03 AM Rafael J. Wysocki wrote: > > > > > > On Thu, Feb 11, 2021 at 1:02 AM Saravana Kannan wrote: > > > > > > > > On Thu, Jan 28, 2021 at 7:03 AM Jon Hunter wrote: > > > > > > > > > > > > > > > On 14/01/2021 16:56, Jon Hunter wrote: > > > > > > > > > > > > On 14/01/2021 16:47, Saravana Kannan wrote: > > > > > > > > > > > > ... > > > > > > > > > > > >>> Yes this is the warning shown here [0] and this is coming from > > > > > >>> the 'Generic PHY stmmac-0:00' device. > > > > > >> > > > > > >> Can you print the supplier and consumer device when this warning is > > > > > >> happening and let me know? That'd help too. I'm guessing the phy is > > > > > >> the consumer. > > > > > > > > > > > > > > > > > > Sorry I should have included that. I added a print to dump this on > > > > > > another build but failed to include here. > > > > > > > > > > > > WARNING KERN Generic PHY stmmac-0:00: supplier 2200000.gpio (status 1) > > > > > > > > > > > > The status is the link->status and looks like the supplier is the > > > > > > gpio controller. I have verified that the gpio controller is probed > > > > > > before this successfully. > > > > > > > > > > > >> So the warning itself isn't a problem -- it's not breaking anything or > > > > > >> leaking memory or anything like that. But the device link is jumping > > > > > >> states in an incorrect manner. With enough context of this code (why > > > > > >> the device_bind_driver() is being called directly instead of going > > > > > >> through the normal probe path), it should be easy to fix (I'll just > > > > > >> need to fix up the device link state). > > > > > > > > > > > > Correct, the board seems to boot fine, we just get this warning. > > > > > > > > > > > > > > > Have you had chance to look at this further? > > > > > > > > Hi Jon, > > > > > > > > I finally got around to looking into this. Here's the email[1] that > > > > describes why it's done this way. > > > > > > > > [1] - https://lore.kernel.org/lkml/YCRjmpKjK0pxKTCP@lunn.ch/ > > > > > > > > > > > > > > The following does appear to avoid the warning, but I am not sure if > > > > > this is the correct thing to do ... > > > > > > > > > > index 9179825ff646..095aba84f7c2 100644 > > > > > --- a/drivers/base/dd.c > > > > > +++ b/drivers/base/dd.c > > > > > @@ -456,6 +456,10 @@ int device_bind_driver(struct device *dev) > > > > > { > > > > > int ret; > > > > > > > > > > + ret = device_links_check_suppliers(dev); > > > > > + if (ret) > > > > > + return ret; > > > > > + > > > > > ret = driver_sysfs_add(dev); > > > > > if (!ret) > > > > > driver_bound(dev); > > > > > > > > So digging deeper into the usage of device_bind_driver and looking at > > > > [1], it doesn't look like returning an error here is a good option. > > > > When device_bind_driver() is called, the driver's probe function isn't > > > > even called. So, there's no way for the driver to even defer probing > > > > based on any of the suppliers. So, we have a couple of options: > > > > > > > > 1. Delete all the links to suppliers that haven't bound. > > > > > > Or maybe convert them to stateless links? Would that be doable at all? > > > > Yeah, I think it should be doable. > > > > > > > > > We'll still leave the links to active suppliers alone in case it helps with > > > > suspend/resume correctness. > > > > 2. Fix the warning to not warn on suppliers that haven't probed if the > > > > device's driver has no probe function. But this will also need fixing > > > > up the cleanup part when device_release_driver() is called. Also, I'm > > > > not sure if device_bind_driver() is ever called when the driver > > > > actually has a probe() function. > > > > > > > > Rafael, > > > > > > > > Option 1 above is pretty straightforward. > > > > > > I would prefer this -> > > > > Ok > > > > > > > > > Option 2 would look something like what's at the end of this email + > > > > caveat about whether the probe check is sufficient. > > > > > > -> because "fix the warning" really means that we haven't got the > > > device link state machine right and getting it right may imply a major > > > redesign. > > > > > > Overall, I'd prefer to take a step back and allow things to stabilize > > > for a while to let people catch up with this. > > > > Are you referring to if/when we implement Option 2? Or do you want to > > step back for a while even before implementing Option 1? > > I would do option 1 and if then see what happens and maybe go back > from there if need be until getting a reasonably stable situation > (that is all of the systems that used to work before still work at > least). Ok, I'll implement Option 1 soon. Also, thinking more about it, I don't like converting it into STATELESS links. It's easy to do, but it doesn't feel right for the driver core to "create" a STATELESS link and then "forget" about it. So, when a device is force bound, I'll just delete the links where the suppliers haven't probed yet. -Saravana