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 36C02C433FE for ; Mon, 14 Feb 2022 11:22:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350992AbiBNLWr (ORCPT ); Mon, 14 Feb 2022 06:22:47 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:49250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347431AbiBNLWi (ORCPT ); Mon, 14 Feb 2022 06:22:38 -0500 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F37133A5F0; Mon, 14 Feb 2022 02:58:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1644836301; x=1676372301; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=fqstnbilWmleOnIjJb3aDPlLE84EFgpMrS7YjBM/2dk=; b=IvgyhlIAVyqiOEPZXCmb4uonwoA85Jcdc5s/4b7laEPWIUs/+35Mffuu S4G+knTiUJKADgopzVw0k+/SHp3N6Jkh8nEuTEqY7r4TMZpKAHqepmtH9 5jXLXjyIn0HUarHtLgXm4EDrqqBM5QkHc+L0VR375kuThCFVyxAXZt1q7 4Tkwa1SUNE41sKHB9pf3x5Rhj2VZ80Ow/pSQmr9f/mRLTExA2AhE0b48T 7OclePP3BUye17yi6yCNCG8EHZwbzde2W7wCRZQTWv9C9aDnovC5UJeM2 iVMGwEsXeaCexXHvX+F8ps/wksDGGyAW4uo6P/MBT1kyPKjST0kuzlWY+ Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10257"; a="250012831" X-IronPort-AV: E=Sophos;i="5.88,367,1635231600"; d="scan'208";a="250012831" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Feb 2022 02:58:20 -0800 X-IronPort-AV: E=Sophos;i="5.88,367,1635231600"; d="scan'208";a="528087732" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.162]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Feb 2022 02:58:15 -0800 Received: by lahna (sSMTP sendmail emulation); Mon, 14 Feb 2022 12:56:58 +0200 Date: Mon, 14 Feb 2022 12:56:58 +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: <20220214085202.GA21533@wunner.de> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Feb 14, 2022 at 09:52:02AM +0100, Lukas Wunner wrote: > On Mon, Feb 14, 2022 at 09:34:26AM +0200, Mika Westerberg wrote: > > On Fri, Feb 11, 2022 at 03:45:46PM -0600, Bjorn Helgaas wrote: > > > My expectation is that "USB" (like "PCI" and "PCIe") tells me > > > something about how a device is electrically connected and how > > > software can operate it. It doesn't really tell me anything about > > > whether those electrical connections are permanent, made through an > > > internal slot, or made through an external connector and cable. > > > > 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? 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 E2467C433EF for ; Mon, 14 Feb 2022 11:30:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351399AbiBNLa2 (ORCPT ); Mon, 14 Feb 2022 06:30:28 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:57758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351650AbiBNLaH (ORCPT ); Mon, 14 Feb 2022 06:30:07 -0500 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D1E96578D; Mon, 14 Feb 2022 03:11:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1644837065; x=1676373065; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=fqstnbilWmleOnIjJb3aDPlLE84EFgpMrS7YjBM/2dk=; b=Q/CnuJHJ+C/XUicMcV3MvkDpTd8wEDQFoAh1eSRxMVo3vTIFecIlCcaO wFfrs0GXUZQLKXxEJAfpbQRYuc7a9ccP0SBrXS9C71l+aAGqGo2vgw6hb EOTst43rgDrvQIxGfDt6mits7HuSSDYKOHgg+L/zpK2sHhQnRS1Hz3lMP s9TYgbnFgwyWC74TYkg84BqB7Q3kUfxJpOImnpyYUPpPZzFg30dw+vnn8 Y/SnJq0ZBP6k9v8FvQn/JWyaSYG89wRnpw6RaUT7rF/lbEjEelGLxqS5I AATFlt50ghPw217yGalq2wri+ktuv2Y9zM86IluhDkHinbt/mJiQVymrp w==; X-IronPort-AV: E=McAfee;i="6200,9189,10257"; a="313347381" X-IronPort-AV: E=Sophos;i="5.88,367,1635231600"; d="scan'208";a="313347381" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Feb 2022 03:11:05 -0800 X-IronPort-AV: E=Sophos;i="5.88,367,1635231600"; d="scan'208";a="501730787" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.162]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Feb 2022 03:10:58 -0800 Received: by lahna (sSMTP sendmail emulation); Mon, 14 Feb 2022 13:08:26 +0200 Date: Mon, 14 Feb 2022 13:08:26 +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: <20220214085202.GA21533@wunner.de> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Message-ID: <20220214110826.65IIbZtIx2-trWYGDB34fhZQGzEVhpLRm9YwPNN-A0w@z> On Mon, Feb 14, 2022 at 09:52:02AM +0100, Lukas Wunner wrote: > On Mon, Feb 14, 2022 at 09:34:26AM +0200, Mika Westerberg wrote: > > On Fri, Feb 11, 2022 at 03:45:46PM -0600, Bjorn Helgaas wrote: > > > My expectation is that "USB" (like "PCI" and "PCIe") tells me > > > something about how a device is electrically connected and how > > > software can operate it. It doesn't really tell me anything about > > > whether those electrical connections are permanent, made through an > > > internal slot, or made through an external connector and cable. > > > > 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?