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=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 DE255C433EF for ; Tue, 14 Sep 2021 16:53:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFF8561159 for ; Tue, 14 Sep 2021 16:53:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231406AbhINQyU (ORCPT ); Tue, 14 Sep 2021 12:54:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:49788 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231254AbhINQyK (ORCPT ); Tue, 14 Sep 2021 12:54:10 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4098A61175 for ; Tue, 14 Sep 2021 16:52:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631638373; bh=5EAvlbhbq0llbBvQjlmqanU1k/OmKujqCYaW1xdICc8=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=NxWci+lLFroCVxuTO0p+EIuaBd24OTW5hJVINSIx9f0Jomwho+oT6dlGWxndYV0mQ dVVPF7pjKWWDD6NCKJnmCnIxI1ow76DdlgWJP02dzEWBlGfuVwjAVKhnu4JWylMG+H jP0FaFKXJsyWOhg9UyoYa81uaOJpXC81Gbs8764ZC3QBK1sDvjYzFxx43Ca0xi/dHH L2lpPTwPBhw82inwr+udP0XhUR0hrDI/60JrzH0vPLddoQx7GvzNLY0nU0UBLXNy2s zq++3h5q12BXXyiKWzhdcPal90hOO3XbA+45xjoDwcj90Oo1JHl4jCV7tnzuR+yQSL C07nOU3PEd98w== Received: by mail-ej1-f49.google.com with SMTP id qq21so24547236ejb.10 for ; Tue, 14 Sep 2021 09:52:53 -0700 (PDT) X-Gm-Message-State: AOAM533xgjyggJL3Wa6KEyXB8ysFU9h+wII5UcCYa9wmj5WxeAuvj8/l DY4s7AyiBg3VkceaT1ndfC8U/2kBtSuX3p98sg== X-Google-Smtp-Source: ABdhPJzlcmTyyKGeLqhCnAJGaPA8O2Oney8+0epWQscPZ1td58g17eux2tseCgGfkEry5Gs0nVA8EUjOCc2B1p/Lvq8= X-Received: by 2002:a17:906:fc09:: with SMTP id ov9mr19911160ejb.128.1631638371795; Tue, 14 Sep 2021 09:52:51 -0700 (PDT) MIME-Version: 1.0 References: <20210914043928.4066136-1-saravanak@google.com> <20210914043928.4066136-6-saravanak@google.com> In-Reply-To: From: Rob Herring Date: Tue, 14 Sep 2021 11:52:38 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v1 5/5] driver core: Add fw_devlink.debug command line boolean parameter To: Andrew Lunn Cc: Saravana Kannan , Greg Kroah-Hartman , "Rafael J. Wysocki" , John Stultz , Marek Szyprowski , Geert Uytterhoeven , Vladimir Oltean , Android Kernel Team , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 14, 2021 at 11:44 AM Andrew Lunn wrote: > > > I did think of this, but the problem is that dynamic debug logs can > > get compiled out (when DYNAMIC_DEBUG isn't set). I think debugging of > > fw_devlink needs to be possible without having to recompile the > > kernel. So in a sense similar to how initcall_debug works today. > > My off the shelf Debian kernel has it enabled. Maybe you can check > other mainline distributions and see if it is enabled by default. Right, I would expect users that can't rebuild their kernel easily would have it enabled. > You are also on a slippery path. You argue this is needed all the time > and add a custom knob. Somebody else adds a new feature which they > also argue always needs bug, and add there own custom knob. We soon > have lots of custom knobs, each doing it slightly differently, in > different places. Chaos. So you need a really good argument why your > code really is special. > > I would suggest you start with dynamic debug, and collect some > statistics of how often you need to ask people to recompile their > kernel. I agree. What would be nice is documenting what needs to be set for devlink. What I used was just 'dyndbg="file drivers/base/core.c +p"' Rob