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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC3ABC433EF for ; Mon, 14 Feb 2022 11:32:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351380AbiBNLcL (ORCPT ); Mon, 14 Feb 2022 06:32:11 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:56464 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351619AbiBNLaT (ORCPT ); Mon, 14 Feb 2022 06:30:19 -0500 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6447066AF7; Mon, 14 Feb 2022 03:12:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1644837121; x=1676373121; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=uhliuFcKaGT4XB0ts+0U1iHxKFUOKpgSPOQ3kJVrBqw=; b=UlwnlLd7Kt5onKh/gt6YHt4vaeoAv2mfWKHqiMKJlm0XTlFhmNw8farZ smdR5+QtyKGbtW7hRkyBc22mcd9/nIIHf5jjH0joZJH4gBnydiSdGudJm e614cm02q6eDo8QYtwzHc4S5SCG1ww1tqv0Tkzz0xUe/k2gUBPYRglBOR Rclx2Besk9IKaDHTaKfKSdo9sVIpJN6vYMOQ6LU92vGA/ROQaQ21LKE+1 +Y+zyeUxZPv9lVyADmfhMUC+FV8fxGe6Jy6HhhNJbLIbtf4sJWUYt1LRT 8qD3jX5Q8Sx2De/8GCD90ncDaPmjz/QVITQLazrUSAHprVIp0OPE1MGI8 Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10257"; a="248901060" X-IronPort-AV: E=Sophos;i="5.88,367,1635231600"; d="scan'208";a="248901060" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Feb 2022 03:12:01 -0800 X-IronPort-AV: E=Sophos;i="5.88,367,1635231600"; d="scan'208";a="538542216" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.162]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Feb 2022 03:11:56 -0800 Received: by lahna (sSMTP sendmail emulation); Mon, 14 Feb 2022 13:11:54 +0200 Date: Mon, 14 Feb 2022 13:11:54 +0200 From: Mika Westerberg To: Lukas Wunner Cc: Bjorn Helgaas , Mario Limonciello , Bjorn Helgaas , "open list:PCI SUBSYSTEM" , "open list:THUNDERBOLT DRIVER" , "open list:RADEON and AMDGPU DRM DRIVERS" , "open list:DRM DRIVERS" , "open list:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS" , Hans de Goede , Michael Jamet , Yehezkel Bernat , Alexander.Deucher@amd.com, Andreas Noever Subject: Re: [PATCH v3 05/12] PCI: Detect root port of internal USB4 devices by `usb4-host-interface` Message-ID: References: <20220211193250.1904843-6-mario.limonciello@amd.com> <20220211214546.GA737137@bhelgaas> <20220214085202.GA21533@wunner.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Mon, Feb 14, 2022 at 01:11:05PM +0200, Mika Westerberg wrote: > > > It is used to identify "tunneled" ports (whether PCIe, USB 3.x or > > > DisplayPort). Tunnels are created by software (in Linux it is the > > > Thunderbolt driver) and are dynamic in nature. The USB4 links go over > > > USB Type-C cable which also is something user can plug/unplug freely. > > > > > > I would say it is reasonable expectation that anything behind these > > > ports can be assumed as "removable". > > > > USB gadgets may be soldered to the mainboard. Those cannot be > > unplugged freely. It is common practice to solder USB Ethernet > > or USB FTDI serial ports and nothing's preventing a vendor to solder > > USB4/Thunderbolt gadgets. > > Right, that's why I say it is "reasonable expectation" that anything > behind these ports can be assumed "removable" :) Of course they don't > have to be but if we assume that in the driver where this actually > matters we should be on the safe side, no? Also the tunnels are not permanent anyway.