Date: Thu, 2 Oct 2025 12:22:45 -0700 From: Mark Millard <marklmi@yahoo.com> To: Alexander Ziaee <ziaee@runbox.com> Cc: 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: <8C91D367-E9E5-4750-AA81-8C673000778E@yahoo.com> In-Reply-To: <E1v4N3j-0004oU-CX@rmmprod06.runbox> References: <E1v4N3j-0004oU-CX@rmmprod06.runbox>
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On Oct 2, 2025, at 10:25, Alexander Ziaee <ziaee@runbox.com> wrote: > 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=3D2f7a796b590e67c5d123f2b00b3aaf7b= a7a32a13 >>>=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. >=20 > 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 is in, allegedly, and so it's existence needs to be mentioned = in the canonical places where we mention our drivers because people are = looking for them for assorted reasons. I've actually booted a Dell Precision 5490 via external USB4 media, but only when it was downstream of a Thunderbolt 3 hub. All 4 USB ports are USB4 on this 5490. And that was some time ago: early 2025-Feb with 1500031 of main 15. It saw the USB4 media as nda0 at nvme0 . This only works as much as it does because the UEFI/ACPI involved supports enough to make some things possible such that FreeBSD does not need to be as involved. As I remember, I set up and did some live-plugging/unlugging experiments any they lead to panics. The configuration had to be as it was at boot time. If I remember right this looked like Thunderbolt 3 mishandling (no surprise). Directly connected, the transition from the kernel to the world/root mount for the USB4 media fails instead. I've not yet tried updating the USB4 media with a more recent FreeBSD main 16 to see what happens now. > Patches to the doc are extremely welcome! I'd need a lot more certainty about interpreting the more informal references that are around vs. the terminology in the USB4 specifications (or other such). I've been more trying to point out subject areas than knowing for sure the details that I used for illustration. > Best, > Alex >=20 >>> +.Sh HISTORY >>> +The >>> +.Nm >>> +driver appeared in >>> +.Fx 15.0 . >>>=20 >>=20 >> =3D=3D=3D >> Mark Millard >> marklmi at yahoo.com >=20 >=20 =3D=3D=3D Mark Millard marklmi at yahoo.com
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