[edk2-devel] Intel NUC platform firmware -- no serial I/O support?

[Nate DeSimone]

Hi Laszlo,

> -----Original Message-----
> From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of Laszlo
> Ersek
> Sent: Thursday, April 7, 2022 12:46 AM
> To: edk2-devel-groups-io <devel at edk2.groups.io>
> Cc: r, ramesh <rameshr at ami.com>; Sivaraman Nainar
> <sivaramann at ami.com>; KARPAGAVINAYAGAM, MANICKAVASAKAM
> <manickavasakamk at ami.com>
> 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: https://github.com/tianocore/edk2-platforms/tree/master/Platform/Intel/BoardModulePkg/LegacySioDxe

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.

Thanks,
Nate
 
> 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 @ami.com 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.
> 
> Thanks!
> Laszlo
> 
> 
> 
> 
> 



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