Re: GPU Passthrough on FreeBSD 14.3(AMD Radeon RX 6700 XT and Debian Linux 12.11)

Petru Garstea <peter.garshtja_at_ambient-md.com> write on
Date: Thu, 28 Aug 2025 17:42:18 UTC :

> I want to mention also that GPU is connected as eGPU via thunderbolt3.


[Do not take the below as claims of an expert. So
believe folks with expertise if they report I'm
wrong about anything.]

Mostly this note is about watching out for assuming
too much of an analogous context with folks that do
not have thunderbolt involved at all in their
context.

If any aspect of what you are doing requires FreeBSD to
support thunderbolt3: I'm not aware that any version
of FreeBSD claims to support any version of thunderbolt
yet. Also, if I understand right, the effort is going
into thunderbolt4+ without initially having general
backward compatibility with thunderbolt3. (That, of
itself, makes the thunderbolt4 incomplete, if I
understand right.)

As I understand, the details even involve if the EFI
software has builtin support for parts of the handling
vs. if the operating system kernel must do those support
activities on on its own. Sometimes some things appear
to work for some contexts because of the EFI dealing
with aspects that the kernel does not deal with (yet).

(As I understand, FreeBSD does not yet face the
alternative of both the EFI and the kernel being able
to support such and guiding which way things should
go.)

===
Mark Millard
marklmi at yahoo.com