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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 82F08C3279B for ; Sun, 8 Jul 2018 13:19:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3352220881 for ; Sun, 8 Jul 2018 13:19:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3352220881 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932867AbeGHNTx (ORCPT ); Sun, 8 Jul 2018 09:19:53 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44394 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932680AbeGHNTw (ORCPT ); Sun, 8 Jul 2018 09:19:52 -0400 Received: from localhost (unknown [46.44.180.42]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id BD90DACC; Sun, 8 Jul 2018 13:19:51 +0000 (UTC) Date: Sun, 8 Jul 2018 15:19:50 +0200 From: Greg Kroah-Hartman To: Javier Martinez Canillas Cc: linux-kernel@vger.kernel.org, Tomeu Vizoso , Rob Herring , Mark Brown , Andy Shevchenko , Peter Robinson , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2] driver core: add a debugfs entry to show deferred devices Message-ID: <20180708131950.GA25366@kroah.com> References: <20180627220656.19298-1-javierm@redhat.com> <20180707155921.GA26504@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 08, 2018 at 02:31:49AM +0200, Javier Martinez Canillas wrote: > Hi Greg, > > On 07/07/2018 05:59 PM, Greg Kroah-Hartman wrote: > > On Thu, Jun 28, 2018 at 12:06:56AM +0200, Javier Martinez Canillas wrote: > >> With Device Trees (DT), the dependencies of the devices are defined in the > >> DT, then the drivers parse that information to lookup the needed resources > >> that have as dependencies. > >> > >> Since drivers and devices are registered in a non-deterministic way, it is > >> possible that a device that is a dependency has not been registered yet by > >> the time that is looked up. > >> > >> In this case the driver that requires this dependency cannot probe and has > >> to defer it. So the driver core adds it to a list of deferred devices that > >> is iterated again every time that a new driver is probed successfully. > >> > >> For debugging purposes it may be useful to know what are the devices whose > >> probe function was deferred. Add a debugfs entry showing that information. > >> > >> $ cat /sys/kernel/debug/devices_deferred > >> 48070000.i2c:twl@48:bci > >> musb-hdrc.0.auto > >> omapdrm.0 > >> > >> This information could be obtained partially by enabling debugging, but it > >> means that the kernel log has to be parsed and the probe deferral balanced > >> with the successes. This can be error probe and has to be done in a ad-hoc > >> manner by everyone who needs to debug these kind of issues. > >> > >> Since the information is already known by the kernel, just show it to make > >> it easier to debug. > >> > >> Signed-off-by: Javier Martinez Canillas > >> Reviewed-by: Mark Brown > > > > This doesn't apply to my tree anymore :( > > > > I see, I made sure that it applied on top of linux-next. > > > Can you rebase and resend? > > > > I guess you want me to rebase on top of your driver-core-next branch. I think > that linux-next should pull that branch instead of the driver-core-linus one: > > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/Next/Trees#n29 Both are in linux-next, it just takes a day or so for the driver-core-next branch to get merged in. thanks, greg k-h