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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C07B8C433ED for ; Fri, 2 Apr 2021 15:07:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91D1761103 for ; Fri, 2 Apr 2021 15:07:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234904AbhDBPHa (ORCPT ); Fri, 2 Apr 2021 11:07:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:58246 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229553AbhDBPH2 (ORCPT ); Fri, 2 Apr 2021 11:07:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5EA2761103; Fri, 2 Apr 2021 15:07:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1617376046; bh=gYmF2FZi4rLr2NP0zXXU+K8L7CMPYgLcBdksf70cB6M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BdrL33DWTrU8wijGjWbo+4VHUlSsOUXZi4osWEN97YcnWYg+aETJzq2kNQY53zWFh pK+zRj7jn6wOgaNlCcCuMJXETRRxNxFW8os+cnXSuhvyfTmXvAAQd0BfbZo3OGmfGf k/s8CYfBx5qVmMmrPJgpGCnsdyOqLmTQTa9BvkZQ= Date: Fri, 2 Apr 2021 17:07:24 +0200 From: Greg Kroah-Hartman To: Saravana Kannan Cc: Rob Herring , Frank Rowand , Stephen Boyd , kernel-team@android.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1] of: property: fw_devlink: Add support for remote-endpoint Message-ID: References: <20210330185056.1022008-1-saravanak@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210330185056.1022008-1-saravanak@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 30, 2021 at 11:50:55AM -0700, Saravana Kannan wrote: > remote-endpoint property seems to always come in pairs where two devices > point to each other. So, we can't really tell from DT if there is a > functional probe order dependency between these two devices. > > However, there can be other dependencies between two devices that point > to each other with remote-endpoint. This non-remote-endpoint dependency > combined with one of the remote-endpoint dependency can lead to a cyclic > dependency[1]. > > To avoid this cyclic dependency from incorrectly blocking probes, > fw_devlink needs to be made aware of remote-endpoint dependencies even > though remote-endpoint dependencies by themselves won't affect probe > ordering (because fw_devlink will see the cyclic dependency between > remote-endpoint devices and ignore the dependencies that cause the > cycle). > > Also, if a device ever needs to know if a non-probe-blocking > remote-endpoint has finished probing, it can now use the sync_state() to > figure it out. > > [1] - https://lore.kernel.org/lkml/CAGETcx9Snf23wrXqjDhJiTok9M3GcoVYDSyNYSMj9QnSRrA=cA@mail.gmail.com/#t > Fixes: ea718c699055 ("Revert "Revert "driver core: Set fw_devlink=on by default""") > Reported-by: Stephen Boyd > Signed-off-by: Saravana Kannan > --- > Rob/Greg, > > This needs to go into driver-core due to the Fixes. Now picked up, thanks. greg k-h