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Date:      Thu, 02 Oct 2025 17:25:39 +0000 (UTC)
From:      "Alexander Ziaee" <ziaee@runbox.com>
To:        "Mark Millard" <marklmi@yahoo.com>, "ziaee" <ziaee@freebsd.org>, "dev-commits-src-main" <dev-commits-src-main@freebsd.org>, "obiwac" <obiwac@freebsd.org>
Subject:   Re: git: 2f7a796b590e - main - thunderbolt.4: Initial manual for HW Relnotes
Message-ID:  <E1v4N3j-0004oU-CX@rmmprod06.runbox>
In-Reply-To: <1F1B3FF4-A31E-4E9C-8CFC-7BB7F1A38AFD@yahoo.com>

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On 2025-10-02 12:47 -04:00 EDT, "Mark Millard" <marklmi@yahoo.com> wrote:
> Alexander Ziaee <ziaee_at_FreeBSD.org> wrote on
> Date: Thu, 02 Oct 2025 15:14:07 UTC :
>=20
>> The branch main has been updated by ziaee:
>>=20
>> URL: https://cgit.FreeBSD.org/src/commit/?id=3D2f7a796b590e67c5d123f2b00=
b3aaf7ba7a32a13
>>=20
>> commit 2f7a796b590e67c5d123f2b00b3aaf7ba7a32a13
>> Author: Alexander Ziaee <ziaee@FreeBSD.org>
>> AuthorDate: 2025-10-02 12:05:25 +0000
>> Commit: Alexander Ziaee <ziaee@FreeBSD.org>
>> CommitDate: 2025-10-02 15:12:48 +0000
>>=20
>> thunderbolt.4: Initial manual for HW Relnotes
>>=20
>> This manual contains nothing and is only suitable for the HW Relnotes,
>> but lets get it in so we have something and then can iterate on it.
>>=20
>> MFC after: 3 minutes
>> Fixes: 2ed9833791f2 (thunderbolt: Import USB4 code)
>> Discussed with: obiwac
>> Differential Revision: https://reviews.freebsd.org/D52847
>> ---
>> share/man/man4/Makefile | 1 +
>> share/man/man4/thunderbolt.4 | 22 ++++++++++++++++++++++
>> 2 files changed, 23 insertions(+)
>>=20
>> diff --git a/share/man/man4/Makefile b/share/man/man4/Makefile
>> index f5d7a0e081fc..6e076722c786 100644
>> --- a/share/man/man4/Makefile
>> +++ b/share/man/man4/Makefile
>> @@ -589,6 +589,7 @@ MAN=3D aac.4 \
>> tdfx.4 \
>> termios.4 \
>> textdump.4 \
>> + thunderbolt.4 \
>> ti.4 \
>> timecounters.4 \
>> tmpfs.4 \
>> diff --git a/share/man/man4/thunderbolt.4 b/share/man/man4/thunderbolt.4
>> new file mode 100644
>> index 000000000000..3477c11fb60d
>> --- /dev/null
>> +++ b/share/man/man4/thunderbolt.4
>> @@ -0,0 +1,22 @@
>> +.\"
>> +.\" Copyright (c) 2025 Alexander Ziaee
>> +.\"
>> +.\" SPDX-License-Identifier: BSD-2-Clause
>> +.\"
>> +.Dd October 2, 2025
>> +.Dt THUNDERBOLT 4
>> +.Os
>> +.Sh NAME
>> +.Nm thunderbolt
>> +.Nd USB4 controller driver
>> +.Sh SYNOPSIS
>> +.Cd device thunderbolt
>> +.Sh HARDWARE
>> +The
>> +.Nm
>> +driver supports USB4 controllers.
>=20
> As I understand things, being fairly explicit related the
> following is likely required (not a proposed wording or
> presentation):
>=20
> Quoting USB4 V2: "A USB4 Host or USB4 Peripheral Device can
> optionally support interoperability with Thunderbolt 3
> (TBT3) products."
>=20
> Quoting USB4 V1: "A USB4 host or USB4 peripheral device can
> optionally support interoperability with Thunderbolt 3
> (TBT3) products."
>=20
> In both, this is tied to Chapter 13, "Interoperability with
> Thunderbolt(tm) 3 systems". As I understand FreeBSD is not
> trying to meet the criteria in that chapter, for example.
>=20
> USB4 does not require a certification process, as I
> remember. Thunderbolt 4 and 5 do, as I remember.
>=20
> As I remember, a distinction between USB4 and Thunderbolt 4
> and 5 was that Thunderbolt 4 and 5 require (nearly?) all
> optional items from the matching USB4 version to be
> implemented (so: not optional if Thunderbolt 4 or 5 is
> claimed/certified). Also, it seems unlikely that FreeBSD
> would go through a Thunderbolt 4 or 5 certification process.
>=20
> Overall this seems to mean not meeting the Thunderbolt 4
> and/or 5 criteria fully and not supporting Thunderbolt 3
> --but just meeting the criteria for one or both of:
>=20
> ) USB4 V1 without "TBT3" support
> ) USB4 V2 without "TBT3" support
>=20
> That would be a subset of the Thunderbolt 4 or 5 criteria
> in a way that excludes Thunderbolt 3.
>=20
> Referencing Thunderbolt without someplace being fairly
> explicit about those types of relationships could easily
> leave a misimpression (even if I've gotten some of the
> status wrong above).
>=20
> My guess here is that enough is known about the intent
> in this area to be able to have material about this type
> of thing in place at any time.

My impression is that actually nothing works yet, but we now have a driver =
called thunderbolt which is made to support these controllers. The driver i=
s in, allegedly, and so it's existence needs to be mentioned in the canonic=
al places where we mention our drivers because people are looking for them =
for assorted reasons.

Patches to the doc are extremely welcome!

Best,
Alex

>> +.Sh HISTORY
>> +The
>> +.Nm
>> +driver appeared in
>> +.Fx 15.0 .
>>=20
>=20
> =3D=3D=3D
> Mark Millard
> marklmi at yahoo.com
>=20
>=20=



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