Some more modern monitors can also be switched by software. I personally use a laptop with an external monitor that is also connected to my desktop. Whenever I need to switch from laptop to desktop (using Barrier or Mouse without Borders on Windows) I then invoke the magic of ControlMyMonitor by the wonderful NirSoft [1] using an Autohotkey-shortcut. This way I can share my monitor with the desktop and laptop. Sharing the keyboard and mouse works with Barrier. I provided some short instructions in an SO-answer [2].

[1] https://www.nirsoft.net/utils/control_my_monitor.html [2] https://superuser.com/a/1556618/299215

Control my monitor is a great find. NirSoft is just full of treasures.

You can switch video inputs using dcc (eg https://www.ddcutil.com/) so you could bind a hotkey to do that or if Synergy/Barrier/Input-leap can be scripted it could do that part too.

There is also a utility that watches for usb device change events on a cheap USB keyboard/mouse (no video) switcher that does the video automatically, but I had it lock up the usb stack on my Linux machine and never really got it to work reliably enough.

I use one of the cheap usb KM switches and changing the input on the monitor manually. Still kind of sucks, but better than nothing.

bumped into reading about ddc a couple times this month now. does this have support across wide number of monitors? i like high refresh rate monitors and want to switch between a macbook and windows pc quickly depending on home/work. seems like a lot of kvms are going to either choke, not have usbc inputs

Not an expert in this by any means, but I think all modern monitors have support for this (eg brightness controls, etc from an applet). Monitors are named, so it supports multiple monitors too.

There are some monitors which act as a KVM for their USB ports. They're rare and hard to find, but they exist.

One (expensive) example: https://www.dell.com/en-us/shop/dell-ultrasharp-30-usb-c-hub...

Modern hdmi (I'd recommend dp versions instead of hdmi) kvm switches aren't very expensive. I'm using a 4 machine hdmi/keyboard/mouse/usb switch that was <$300. They make dual monitor ones too. Tho I just use a cheap hdmi switch for my secondary monitor because it doesn't emulate a connection to the PC while a different input is selected.

This allows me to extend my active desktop to two monitors, or show a different machine on the secondary monitor. I also use barrier for this two host configuration.

No need for additional hardware. Take two Barrier-connected computers, the mouse can travel from one screen to the other. When using the keyboard, it inputs on the monitor with the mouse focus. Since it's UI based you need a screen per device yes.

Have been using hardware KVM switches (HDMI/USB) from Belkin and some unknown brands from AliExpress since years. I don't remember the price exactly, but it was way under $100. I even contacted the Chinese manufacturer to change the PCB for me (I wanted the ports repositioned) and they did a very good and quick job for under $300. I'm talking dual computers in this case, not more.

Depends on your price range I guess. You can find iogear/belkin HDMI 4 port switches for a bit under $100. Generic ones will be even less (maybe even around $50). I personally use DVI KVM from iogear (GCS1104) which cost me about $130, one of my machines is a gaming rig with Nvidia card and it works flawlessly.

I use a multipairing mouse and keyboard (Logitech MX Keys and MX Anywhere) and have my personal laptop connect via Thunderbolt → DVI and work via HDMI. It means I have to press three buttons to switch but it's still pretty convenient, without the expense of a dedicated KVM solution.