kvm-switch

I went down a similar rabbit hole a while back and ended up building something that attacks the same problem from the opposite direction: instead of just a hardware box that switches everything (video + USB), I wrote Fence[1], a software layer that automates switching USB input devices when you glide the mouse to the edge of the screen. The idea is basically "Synergy's convenience, but with real hardware switching." You run a tiny client on each machine. When your cursor hits the left edge of your desktop, Fence tells a USB and HDMI Switch to physically redirect your keyboard and mouse to the next PC. The switching happens in hardware and you can design your layout per-direction and per-device. Where the L1T KVM is the "one box handles video and IO beautifully" approach, Fence is more of an "IO routing layer" that lets you keep your exist

With my COVID obsession of live streaming while writing code, I ended up building something a little more elaborate. https://github.com/timgws/kvm-switch It doesn't use DDC commands direct to the monitor(s), instead swapping it for a HDMI matrix combined with a traditional KVM for swapping around inputs smoothly when you roll your mouse over the edge of different operating systems. The switching client runs on Windows, MacOS and Linux (if you use X).

I had the same issue with this device. I ended up writing some code that you could run on a machine to operate the switching via the RS232 port: https://github.com/timgws/kvm-switch/ Bonus for adding 'glide and switch' functionality, so you can move the mouse to the edge of the screen and it would jump the input to the next display in your layout. It's like a hardware version of Synergy. Very finicky device, but if you don't touch it - and you don't use any of the shortcuts - it works.

The proverb 'necessity is the mother of invention' made me build a solution for sharing a keyboard and mouse between multiple devices. Synergy/Barrier is not horrible, but I find the latency a little painful. Ended up getting an industrial HDMI switch, with a KVM. Built a server in Go that connects to the serial port of all the devices. A companion client that runs on all the machines tells the server when the mouse moves to the edge of the screen, so the USB inputs can be switched to the correct computer. Basically, it allows you to have multiple computers connected, to multiple displays, sharing one keyboard and mouse. (You can define layouts on the server, so the displays can move around on the matrix HDMI switcher). https://github.com/timgws/kvm-switch