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From: Theo <theom+news@chiark.greenend.org.uk>
Newsgroups: comp.sys.raspberry-pi
Subject: Re: Laptop as KVM to access RasPi
Date: 17 Jul 2025 12:39:24 +0100 (BST)
Organization: University of Cambridge, England
Message-ID: <ioE*7GJhA@news.chiark.greenend.org.uk>
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mm0fmf <none@invalid.com> wrote:
> On 15/07/2025 21:04, druck wrote:
> > On 11/07/2025 07:30, mm0fmf wrote:
> >> On 11/07/2025 06:23, David Taylor wrote:
> >>> On 11/07/2025 01:37, vjp2.at@at.BioStrategist.dot.dot.com wrote:
> >>>> If I connect the RasPi to my laptop by USB is there any software
> >>>> which allows my laptop to be KVM (Keyboard, Video, Mouse)?
> >>>>
> >>>> PuTTY may work, but it doesn't have graphics.
> >>>
> >>> I recall PuTTY having some X11 extension, but I use VNC which, I 
> >>> suspect, is LAN/WiFi only.
> >>
> >> Setup RNDIS and you have a network connection between the two over USB.
> > 
> > The first search hit on RNDIS for Linux was how they are trying to 
> > expunge the horribly insecure Microsoft protocol from the Linux kernel!
> > 
> > ---druck
> Oh noes!!!!!! MS and insecure protocols.
> 
> Yes, RNDIS is insecure. But do you know what, if you allow someone to 
> plug any random device into your computer then insecure protocols are 
> the least of your problems. If it's your device and your computer then 
> it's no big deal.

If it's your device and your computer you could just use CDC-NCM instead. 
I've used that successfully between Pi-like devices (Beaglebone Black) and
FreeBSD servers.

Here's the script, based on the Beaglebone Linux's bb-usb-gadgets package:
https://github.com/CTSRD-CHERI/morello-bbb-ubuntu-image-builder/blob/master/morello/bb-start-acm-ncm-rndis-old-gadget

It does some combination of USB serial (CDC-ACM), mass storage, RNDIS and
NCM depending on which options you pick.

Theo