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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 ABA35C433E0 for ; Mon, 18 Jan 2021 17:41:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8445422CA0 for ; Mon, 18 Jan 2021 17:41:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436624AbhARRkx (ORCPT ); Mon, 18 Jan 2021 12:40:53 -0500 Received: from mail-ot1-f48.google.com ([209.85.210.48]:46495 "EHLO mail-ot1-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2407199AbhARRkJ (ORCPT ); Mon, 18 Jan 2021 12:40:09 -0500 Received: by mail-ot1-f48.google.com with SMTP id w3so17005010otp.13; Mon, 18 Jan 2021 09:39:46 -0800 (PST) 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=TBu9By/8VRPgsqkSVXbZt+m8ccctd/56lGbUNRtH3tI=; b=J6pVmnYr9M37tfcBZLsOeNhXDxnQvYM0uAe+L9wWWr1uPxHUxPamXdPt9mqi0YjUcx Aq+ypNJp7aJtZ3vZoDw7+B4ek2OCKwUhfHZ9KOZ6c77tsdOzyBoP6oZOZ142qlZE6HmU lkgEBB58SadOuB4qxNfnYOwk5QZ02npy1lE3Z1eI/3i1M+Kl8AUp3Wq95cOj3w4LJsUr le4ClMM/GZgJno7xGvEj18ZsrHl5LbYXVbpVfMoxtBc2/Clp9d3Bna4NerZCe0JRSZGc +p//I5gEB+9MwZL6fl82USiL8Y1QStZTuEKgBfClzz9osWsHOLVB6jjTb7IRvw8nnILA Yjrg== X-Gm-Message-State: AOAM530ASu9aqiR1226g/abQME1rfL1wIj67HuEJR6/j3uce6Z7ZWM+E bU3QEaZt46jtkF2MPK3u11N9jDXEKFRNsS+eMB8= X-Google-Smtp-Source: ABdhPJxUhvwAbVRYw3irl60YU62M+0M0hOssaiRs12vpO3+6daUkruZv7J346RSH/KO6+zjS42brpnTnh56DPMc/u8Q= X-Received: by 2002:a05:6830:210a:: with SMTP id i10mr458499otc.145.1610991561344; Mon, 18 Jan 2021 09:39:21 -0800 (PST) MIME-Version: 1.0 References: <20201218031703.3053753-1-saravanak@google.com> <20201218031703.3053753-6-saravanak@google.com> In-Reply-To: <20201218031703.3053753-6-saravanak@google.com> From: Geert Uytterhoeven Date: Mon, 18 Jan 2021 18:39:10 +0100 Message-ID: Subject: Re: [PATCH v1 5/5] driver core: Set fw_devlink=on by default To: Saravana Kannan Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , Android Kernel Team , Linux Kernel Mailing List , Jisheng Zhang , Kevin Hilman , John Stultz , Nicolas Saenz Julienne , Marc Zyngier , Yoshihiro Shimoda , Linux-Renesas Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Saravana, On Fri, Dec 18, 2020 at 4:34 AM Saravana Kannan wrote: > Cyclic dependencies in some firmware was one of the last remaining > reasons fw_devlink=on couldn't be set by default. Now that cyclic > dependencies don't block probing, set fw_devlink=on by default. > > Setting fw_devlink=on by default brings a bunch of benefits (currently, > only for systems with device tree firmware): > * Significantly cuts down deferred probes. > * Device probe is effectively attempted in graph order. > * Makes it much easier to load drivers as modules without having to > worry about functional dependencies between modules (depmod is still > needed for symbol dependencies). > > If this patch prevents some devices from probing, it's very likely due > to the system having one or more device drivers that "probe"/set up a > device (DT node with compatible property) without creating a struct > device for it. If we hit such cases, the device drivers need to be > fixed so that they populate struct devices and probe them like normal > device drivers so that the driver core is aware of the devices and their > status. See [1] for an example of such a case. > > [1] - https://lore.kernel.org/lkml/CAGETcx9PiX==mLxB9PO8Myyk6u2vhPVwTMsA5NkD-ywH5xhusw@mail.gmail.com/ > Signed-off-by: Saravana Kannan Shimoda-san reported that next-20210111 and later fail to boot on Renesas R-Car Gen3 platforms. No output is seen, unless earlycon is enabled. I have bisected this to commit e590474768f1cc04 ("driver core: Set fw_devlink=on by default"). Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds