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From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org,
	Andreas Noever <andreas.noever@gmail.com>,
	Michael Jamet <michael.jamet@intel.com>,
	Yehezkel Bernat <YehezkelShB@gmail.com>,
	Rajmohan Mani <rajmohan.mani@intel.com>,
	Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>,
	Lukas Wunner <lukas@wunner.de>,
	Alan Stern <stern@rowland.harvard.edu>,
	Mario.Limonciello@dell.com,
	Anthony Wong <anthony.wong@canonical.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 00/22] thunderbolt: Add support for USB4
Date: Tue, 1 Oct 2019 16:42:47 +0300
Message-ID: <20191001134247.GT2714@lahna.fi.intel.com> (raw)
In-Reply-To: <20191001124954.GI2954373@kroah.com>

On Tue, Oct 01, 2019 at 02:49:54PM +0200, Greg Kroah-Hartman wrote:
> On Tue, Oct 01, 2019 at 02:38:08PM +0300, Mika Westerberg wrote:
> > Hi all,
> > 
> > I'm sending this as RFC because the series is still missing important
> > features such as power management so not ready for merging. However, I
> > think it is good to get any early feedback from the community. We are
> > working to add support for the missing features.
> > 
> > USB4 is the public specification of Thunderbolt 3 protocol and can be
> > downloaded here:
> > 
> >   https://www.usb.org/sites/default/files/USB4%20Specification_1.zip
> > 
> > USB4 is about tunneling different protocols over a single cable (in the
> > same way as Thunderbolt). The current USB4 spec supports PCIe, Display Port
> > and USB 3.x, and also software based protocols such as networking between
> > domains (hosts).
> > 
> > So far PCs have been using firmware based Connection Manager and Apple
> > systems have been using software based one. A Connection Manager is the
> > entity that handles creation of different tunnel types through the USB4
> > (and Thunderbolt) fabric. With USB4 the plan is to have software based
> > Connection Manager everywhere but some early systems will also support
> > firmware to allow OS downgrade for example.
> > 
> > Current Linux Thunderbolt driver supports both "modes" and can detect which
> > one to use dynamically.
> > 
> > This series first adds support for Thunderbolt 3 devices to the software
> > connection manager and then extends that to support USB4 compliant hosts
> > and devices (this applies to both firmware and software based connection
> > managers). With this series the following features are supported also for
> > USB4 compliant devices:
> > 
> >   - PCIe tunneling
> >   - Display Port tunneling
> >   - USB 3.x tunneling
> >   - P2P networking (implemented in drivers/net/thunderbolt.c)
> >   - Host and device NVM firmware upgrade
> > 
> > We also add two new sysfs attributes under each device that expose link
> > speed and width to userspace. The rest of the userspace ABI stays the same.
> > 
> > I'm including Linux USB folks as well because USB4 is officially coming
> > from USB-IF which puts us on same boat now.
> > 
> > While I changed the user visible Kconfig string to mention "USB4" (the
> > Kconfig option is still CONFIG_THUNDERBOLT), I'm wondering whether we
> > should move the whole Thunderbolt driver under drivers/usb/thunderbolt as
> > well? 
> 
> Looks "interesting", nice work!

Thanks!

> I stopped at patch "Add initial support for USB4" as I don't think we
> want to add USB4 code to a system that we know does not have it, right?

You can connect a USB4 device to Thunderbolt 3 system. USB4 hubs
specifically are required to support this by the spec. Of course then it
is in Thunderbolt 3 alternate mode (not in USB4 native mode) but the
USB4 register set is still there. So for example we still need to
configure TMU (Time Management Unit) and access the DROM via router
operations and so on.

Do you mean we don't want that?

> Everything up to then is just "normal" thunderbolt, and with the
> exception of a few minor comments, all look fine to me.
> 
> I didn't actually read the USB4 patch just yet, as I figured we needed
> to argue about that some more :)

Heh, sure and thanks for the feedback so far :)

      reply index

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-01 11:38 Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 01/22] thunderbolt: Introduce tb_switch_is_icm() Mika Westerberg
2019-10-01 12:10   ` Greg Kroah-Hartman
2019-10-01 12:46     ` Mika Westerberg
2019-10-01 13:36       ` Mario.Limonciello
2019-10-01 13:48         ` Mika Westerberg
2019-10-01 13:50           ` Mario.Limonciello
2019-10-01 13:52             ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 02/22] thunderbolt: Log switch route string on config read/write timeout Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 03/22] thunderbolt: Log warning if adding switch fails Mika Westerberg
2019-10-01 12:18   ` Greg Kroah-Hartman
2019-10-01 12:48     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 04/22] thunderbolt: Make tb_sw_write() take const parameter Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 05/22] thunderbolt: Add helper macros to iterate over switch ports Mika Westerberg
2019-10-02 14:17   ` Oliver Neukum
2019-10-02 14:28     ` Mika Westerberg
2019-10-06 12:15       ` Lukas Wunner
2019-10-01 11:38 ` [RFC PATCH 06/22] thunderbolt: Add support for lane bonding Mika Westerberg
2019-10-01 12:38   ` Greg Kroah-Hartman
2019-10-01 12:53     ` Mika Westerberg
2019-10-02 14:21       ` Oliver Neukum
2019-10-02 14:30         ` Mika Westerberg
2019-10-03  8:25           ` Oliver Neukum
2019-10-03  8:53             ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 07/22] thunderbolt: Add default linking between ports if not provided by DROM Mika Westerberg
2019-10-01 12:39   ` Greg Kroah-Hartman
2019-10-01 13:14     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 08/22] thunderbolt: Add downstream PCIe port mappings for Alpine and Titan Ridge Mika Westerberg
2019-10-01 12:40   ` Greg Kroah-Hartman
2019-10-01 13:27     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 09/22] thunderbolt: Convert basic adapter register names to follow the USB4 spec Mika Westerberg
2019-10-01 12:41   ` Greg Kroah-Hartman
2019-10-01 13:28     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 10/22] thunderbolt: Convert PCIe adapter register names to use USB4 names Mika Westerberg
2019-10-01 12:42   ` Greg Kroah-Hartman
2019-10-01 11:38 ` [RFC PATCH 11/22] thunderbolt: Convert DP adapter register names to follow the USB4 spec Mika Westerberg
2019-10-01 12:42   ` Greg Kroah-Hartman
2019-10-01 11:38 ` [RFC PATCH 12/22] thunderbolt: Add Display Port CM handshake for Titan Ridge devices Mika Westerberg
2019-10-01 12:44   ` Greg Kroah-Hartman
2019-10-01 13:30     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 13/22] thunderbolt: Add Display Port adapter pairing and resource management Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 14/22] thunderbolt: Add bandwidth management for Display Port tunnels Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 15/22] thunderbolt: Make tb_find_port() available to other files Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 16/22] thunderbolt: Call tb_eeprom_get_drom_offset() from tb_eeprom_read_n() Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 17/22] thunderbolt: Add initial support for USB4 Mika Westerberg
2019-10-01 12:47   ` Greg Kroah-Hartman
2019-10-01 13:09     ` Mika Westerberg
2019-10-01 14:53       ` Greg Kroah-Hartman
2019-10-01 14:59         ` Mario.Limonciello
2019-10-01 15:13           ` Mika Westerberg
2019-10-01 15:22           ` Greg KH
2019-10-01 15:32             ` Mika Westerberg
2019-10-01 15:07         ` Mika Westerberg
2019-10-01 15:19           ` Greg Kroah-Hartman
2019-10-01 15:26             ` Mika Westerberg
2019-10-01 16:27           ` Oliver Neukum
2019-10-02  8:30             ` Mika Westerberg
2019-10-02  8:39               ` Greg Kroah-Hartman
2019-10-02  8:49                 ` Mika Westerberg
2019-10-01 17:05   ` Mario.Limonciello
2019-10-01 18:14     ` Mario.Limonciello
2019-10-02  8:39       ` Mika Westerberg
2019-10-02 15:09         ` Mario.Limonciello
2019-10-02 15:36           ` Yehezkel Bernat
2019-10-02 16:00             ` Mario.Limonciello
2019-10-03  8:00               ` Mika Westerberg
2019-10-03 14:41                 ` Mario.Limonciello
2019-10-04  7:54                   ` Mika Westerberg
2019-10-04  8:07                     ` Yehezkel Bernat
2019-10-04  8:19                       ` Mika Westerberg
2019-10-04 11:19                         ` Yehezkel Bernat
2019-10-04 14:05                           ` Mario.Limonciello
2019-10-04 14:19                             ` Mario.Limonciello
2019-10-04 14:21                             ` Mika Westerberg
     [not found]                               ` <1570201357.2.0@kellner.me>
2019-10-04 15:16                                 ` Mika Westerberg
2019-10-04 15:22                                   ` Christian Kellner
2019-10-02  8:34     ` Mika Westerberg
2019-10-02 15:04       ` Mario.Limonciello
2019-10-01 11:38 ` [RFC PATCH 18/22] thunderbolt: Make tb_switch_find_cap() available to other files Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 19/22] thunderbolt: Add support for Time Management Unit Mika Westerberg
2019-10-02 16:52   ` Mani, Rajmohan
2019-10-03  8:01     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 20/22] thunderbolt: Add support for USB tunnels Mika Westerberg
2019-10-03  8:42   ` Oliver Neukum
2019-10-03  8:52     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 21/22] thunderbolt: Update documentation with the USB4 information Mika Westerberg
2019-10-01 14:17   ` Mario.Limonciello
2019-10-01 14:21     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 22/22] thunderbolt: Do not start firmware unless asked by the user Mika Westerberg
2019-10-01 14:43   ` Mario.Limonciello
2019-10-01 14:58     ` Mika Westerberg
2019-10-01 16:53       ` Mario.Limonciello
2019-10-02  8:48         ` Mika Westerberg
2019-10-01 12:49 ` [RFC PATCH 00/22] thunderbolt: Add support for USB4 Greg Kroah-Hartman
2019-10-01 13:42   ` Mika Westerberg [this message]

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