Re: Intel NUC platform firmware -- no serial I/O support?

Nate DeSimone

Hi Laszlo,

-----Original Message-----
From: <> On Behalf Of Laszlo
Sent: Thursday, April 7, 2022 12:46 AM
To: edk2-devel-groups-io <>
Cc: r, ramesh <rameshr@...>; Sivaraman Nainar
Subject: [edk2-devel] Intel NUC platform firmware -- no serial I/O support?

Hi List,

my toolbox has been extended with an Intel NUC, the base kit model being
NUC8i3PNH. The NUC has a serial port connector on the back, and indeed
Serial I/O works fine once an OS starts.

However, the UEFI platform firmware seems to have no support for Serial
I/O. I've built a fresh UEFI Shell binary from edk2 master and poked around in
the protocol database, with "drivers" and "dh". The necessary drivers seem
to be included, however they do not appear to bind the hardware that's
inside the chassis. ("connect -r" makes no difference in this regard, so it's not
just BDS policy.)
Yeah you are right the Super I/O stuff is barrels of fun. However it is actually a spec defined protocol, it is just in the PI spec not the UEFI spec. The PI spec also counts for addition to MdePkg. On the MinPlatform side we built a small/simple Super I/O bus driver for UARTs and PS/2 keyboard/mouse:

Volume 5, Chapter 14 of the PI spec waxes rather poetic about how to build a full ISA plug-and-play capable DXE driver stack for a system that incorporates both a Super I/O and physical ISA slots.

I can say is that the NUC team has opted to build their systems with AMI Aptio instead of starting with the Intel reference UEFI firmware. I'm not privy to the conversation there. Accordingly, there might be some Aptio specific drivers as you note in your listing of the driver handle database. I'm afraid I have as much knowledge about how that driver stack works as you do.


Interestingly, the related drivers are all called "AMI ...", which I find
somewhat strange on an Intel-branded NUC. I don't know whom I should be
addressing with my question in the first place. Just to be sure, I'm CC'ing a
bunch of randomly picked email addresses from my edk2-devel
list archive.

I can provide more details if needed, but first I'd like to ask if *any* firmware
update exists for this kit -- NUC8i3PNH -- where the platform firmware can
drive the serial port. My goal is (of course) completely headless operation of
the NUC; ideally, that would cover the UEFI console too.

Right now, I need to connect an HDMI monitor and a USB keyboard+mouse
to the NUC just to get into the Setup UI / UEFI Shell.


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