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=-6.0 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 148AEC433FE for ; Sun, 6 Dec 2020 09:07:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0B002087D for ; Sun, 6 Dec 2020 09:07:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726239AbgLFJHD (ORCPT ); Sun, 6 Dec 2020 04:07:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:53252 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725767AbgLFJHC (ORCPT ); Sun, 6 Dec 2020 04:07:02 -0500 Date: Sun, 6 Dec 2020 11:06:14 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1607245581; bh=s+w0DJiO0lLkfTm14BP/G28WyCllLXEdBVKQ6c423Ag=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=gagO/krH5WjoJg2V+3NWtbbaWM9kYMbV6eKBL2Ee/hDqf7FozNpVol+hrpDbIrtzB 4/F5hCSHkP7ZCztYSosF/OFCNjQ8oUE1NR5roXgLNT/yx7h/iAoBYWUxXCB1/zr7EK eZ5Zy13XqlwZop+t0NGSqQwlAcBb68iNRQgLcAn8Y2fIVgXOHC6cQxAoLlQaft8hrT yuZDmYadfJGWBNMYXpGRffTk+vGVMaG+bYk/GxtDiSljdpNyjry2rDM9v85xszhavW QsZz1nQYp3O2Y3htOOOXGHGcSeT5O3fnmHTDf6KOV/G3/UfK9NfoUPsIElNKcruTMR 46FyyPilulOEg== From: Leon Romanovsky To: =?utf-8?B?Qmxhxb4=?= Hrastnik Cc: Hans de Goede , Maximilian Luz , Greg Kroah-Hartman , lkml , Mark Gross , Andy Shevchenko , =?utf-8?Q?Barnab=C3=A1s_P=C5=91cze?= , Arnd Bergmann , Rob Herring , Jiri Slaby , "Rafael J . Wysocki" , Len Brown , Steven Rostedt , Ingo Molnar , Masahiro Yamada , Michal Marek , Jonathan Corbet , Dorian Stoll , platform-driver-x86@vger.kernel.org, linux-serial@vger.kernel.org, linux-acpi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v2 0/9] Add support for Microsoft Surface System Aggregator Module Message-ID: <20201206090614.GA693271@unreal> References: <20201203212640.663931-1-luzmaximilian@gmail.com> <20201206070705.GA686270@unreal> <052ecf4d-9e08-2c08-8a06-c30ba2b28d82@redhat.com> <1b4fe1fd-592d-4a88-b156-fbf6af2df428@www.fastmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1b4fe1fd-592d-4a88-b156-fbf6af2df428@www.fastmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Dec 06, 2020 at 05:58:32PM +0900, Blaž Hrastnik wrote: > > > > > More on that, the whole purpose of proposed interface is to debug and > > > not intended to be used by any user space code. > > > > The purpose is to provide raw access to the Surface Serial Hub protocol, > > just like we provide raw access to USB devices and have hidraw devices. > > > > So this goes a litle beyond just debugging; and eventually the choice > > may be made to implement some functionality with userspace drivers, > > just like we do for some HID and USB devices. > > > > Still I agree with you that adding new userspace API is something which > > needs to be considered carefully. So I will look at this closely when > > reviewing this set. > > To add to that: this was previously a debugfs interface but was moved to misc after review on the initial RFC: > https://lkml.org/lkml/2020/9/24/96 There is a huge difference between the suggestion and final implementation. Greg suggested to add new debug module to the drivers/misc that will open char device explicitly after user loaded that module to debug this hub. However, the author added full blown char device as a first citizen that has all not-break-user constrains. Thanks