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 E0C37C77B75 for ; Tue, 23 May 2023 12:54:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236840AbjEWMyl (ORCPT ); Tue, 23 May 2023 08:54:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234328AbjEWMyk (ORCPT ); Tue, 23 May 2023 08:54:40 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5F29126 for ; Tue, 23 May 2023 05:54:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1684846477; x=1716382477; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=9eVLmuqblr0h9AVJ8GhHamXZ4+6PTBY/o5MU8TGsQi4=; b=Uva0nGPsFyJ62vi6IOtBT5ltvQfIAzx40dVfzSsO8LmwbYUSI8a0Z0l9 ziTCWDnb7hE0RFG43eV+qDleDYaROblS266HBib/N+oJJJufvOZF9EDdd QhW2jeFSDSyuM5yMZGL2ccaiUK9XI3OfpjTfClVnhEf1IMQxjAYJY+FH+ w3/6uWaQy0SZVBndGo9+cTGsds/L9gTJP6PfJ1fAIpDUNRg3QRW+LYX+6 l8vE5emKhd6z1izioCRBJvgVbqzYXzBdEWawgTbnxwUFWBI2o7twUHWit uS9zzN5Y9Ru9xYv7OP2jRY7nm66cEL2Bn8EMU8BdMO0xgyYUC04/la/cZ A==; X-IronPort-AV: E=McAfee;i="6600,9927,10719"; a="333588683" X-IronPort-AV: E=Sophos;i="6.00,186,1681196400"; d="scan'208";a="333588683" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 May 2023 05:54:37 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10719"; a="706993610" X-IronPort-AV: E=Sophos;i="6.00,186,1681196400"; d="scan'208";a="706993610" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga007.fm.intel.com with ESMTP; 23 May 2023 05:54:35 -0700 Received: by black.fi.intel.com (Postfix, from userid 1001) id 5B2813B9; Tue, 23 May 2023 15:54:39 +0300 (EEST) Date: Tue, 23 May 2023 15:54:39 +0300 From: "mika.westerberg@linux.intel.com" To: =?utf-8?B?TW/FhCw=?= Tomasz Cc: "YehezkelShB@gmail.com" , "andreas.noever@gmail.com" , "michael.jamet@intel.com" , "linux-usb@vger.kernel.org" Subject: Re: USB 2.0 host controller for Thunderbolt 4 Message-ID: <20230523125439.GP45886@black.fi.intel.com> References: <20230523090132.GO45886@black.fi.intel.com> <551c6ce270bac239fbcebd5280e426851b84ee0e.camel@nordicsemi.no> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <551c6ce270bac239fbcebd5280e426851b84ee0e.camel@nordicsemi.no> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Tue, May 23, 2023 at 09:45:49AM +0000, Moń, Tomasz wrote: > On Tue, 2023-05-23 at 12:01 +0300, Mika Westerberg wrote: > > On Tue, May 23, 2023 at 10:53:17AM +0200, Tomasz Moń wrote: > > > When I connect Thunderbolt 3 dock, two new host controllers show up: > > > * usb5 - USB 2.0 High-Speed > > > * usb6 - USB 3.0 SuperSpeed > > > > > > Devices connected through Thunderbolt 3 dock end up on expected host > > > controllers, i.e. Low/Full/High-Speed devices connect to usb5 and > > > SuperSpeed devices end up on usb6. > > > > > > Is Thunderbolt 3 essentially tunnelling the USB 2.0 traffic (by > > > tunnelling PCIe xHCI host controller traffic) on the superspeed > > > differential pairs (operating in alternate TBT3 mode)? > > > > It is not. The USB 2.x wires are separate on type-C cables. > > Yes, the USB 2.x wires are separate on type-C cables. But this does not > answer the question why there is new USB 2.0 High-Speed controller > showing up that the devices do connect to. So for the xHCI on the dock itself, I think this is what you mean, it is just a normal PCIe endpoint and all that traffic goes over a PCIe tunnel, including the USB 2.x.