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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 29DE9C433F5 for ; Tue, 21 Sep 2021 21:03:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04213611C6 for ; Tue, 21 Sep 2021 21:03:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231592AbhIUVEm (ORCPT ); Tue, 21 Sep 2021 17:04:42 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:52850 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233740AbhIUVEi (ORCPT ); Tue, 21 Sep 2021 17:04:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=prpIZcxjvdXTKyMRNo5Wbn7PrK6WuARtzohRlOC6YHU=; b=2WvwaUkUIq1tNnXUQuhHTtZ5wd fBMTVNrGTpiogLWrUqRBTgeI7zYujZQ5bu+Zs84B3OyGCrlZf2nDBbVs3ZkkZomRO920dAGLU58dh Z9q52nNVmVyvnHYRRy8heqQGFXL/DuZi6snFXMtvluRXE28LHJwk/gAHvGf1lInesPS4=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1mSmun-007gZb-UF; Tue, 21 Sep 2021 23:02:57 +0200 Date: Tue, 21 Sep 2021 23:02:57 +0200 From: Andrew Lunn To: Saravana Kannan Cc: "Rafael J. Wysocki" , Greg Kroah-Hartman , Heiner Kallweit , Russell King , "David S. Miller" , Jakub Kicinski , Len Brown , Geert Uytterhoeven , Vladimir Oltean , "Cc: Android Kernel" , Linux Kernel Mailing List , netdev , ACPI Devel Maling List Subject: Re: [PATCH v3 2/3] driver core: fw_devlink: Add support for FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD Message-ID: References: <20210915170940.617415-1-saravanak@google.com> <20210915170940.617415-3-saravanak@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org > There are cases where the children try to probe too quickly (before > the parent has had time to set up all the resources it's setting up) > and the child defers the probe. Even Andrew had an example of that > with some ethernet driver where the deferred probe is attempted > multiple times wasting time and then it eventually succeeds. And i prefer an occasional EPROBE_DEFER over a broken Ethernet switch, which is the current state. I'm happy to see optimisations, but not at the expense of breaking working stuff. > Also, this assumption that the child will be bound successfully upon > addition forces the parent/child drivers to play initcall chicken We have never had any initcall chicken problems. The switch drivers all are standard mdio_module_driver, module_platform_driver, module_i2c_driver, module_pci_driver. Nothing special here. Things load in whatever order they load, and it all works out, maybe with an EPROBE_DEFER cycle. Which is good, we get our error paths tested, and sometimes find bugs that way. Andrew