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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E7E58C433EF for ; Mon, 14 Feb 2022 14:19:39 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4EE7910E32F; Mon, 14 Feb 2022 14:19:39 +0000 (UTC) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id AABF410E4FB; Mon, 14 Feb 2022 11:11:05 +0000 (UTC) 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="249816998" X-IronPort-AV: E=Sophos;i="5.88,367,1635231600"; d="scan'208";a="249816998" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.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 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 X-Mailman-Approved-At: Mon, 14 Feb 2022 14:19:38 +0000 X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andreas Noever , Michael Jamet , "open list:PCI SUBSYSTEM" , "open list:DRM DRIVERS" , "open list:THUNDERBOLT DRIVER" , Yehezkel Bernat , "open list:RADEON and AMDGPU DRM DRIVERS" , Hans de Goede , Bjorn Helgaas , Mario Limonciello , "open list:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS" , Bjorn Helgaas , Alexander.Deucher@amd.com Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7250FC433FE for ; Mon, 14 Feb 2022 14:19:44 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 39F7510E51A; Mon, 14 Feb 2022 14:19:43 +0000 (UTC) Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 46ADB10E4FA; Mon, 14 Feb 2022 10:58:21 +0000 (UTC) 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="310803286" X-IronPort-AV: E=Sophos;i="5.88,367,1635231600"; d="scan'208";a="310803286" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga104.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 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 X-Mailman-Approved-At: Mon, 14 Feb 2022 14:19:38 +0000 X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andreas Noever , Michael Jamet , "open list:PCI SUBSYSTEM" , "open list:DRM DRIVERS" , "open list:THUNDERBOLT DRIVER" , Yehezkel Bernat , "open list:RADEON and AMDGPU DRM DRIVERS" , Hans de Goede , Bjorn Helgaas , Mario Limonciello , "open list:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS" , Bjorn Helgaas , Alexander.Deucher@amd.com Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" Message-ID: <20220214105658.SZVkYiUe_KUEOdFuOqnr0-ntfoCLQrQIIaO94WD1AHo@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?