Zero fiddling, but substantial financial outlay
Any somewhat-modern monitor with multiple outputs should be able to do this. DDC support has been around for a while
Two computers, one monitor, zero fiddling (2025)
11–20 of 153 posts
Re: Two computers, one monitor, zero fiddling (2025)
#12I did something similar last year with a monitor without built-in KVM but with good DCC support (Ultrasharp U3417W) and Synergy [0].
I use Synergy as part of my desk setup already, but needed a way to view the UI of a normally headless machine. The solution I built was a small shell script that terminated the active Synergy session and started a new one with a different config file (so keyboard/mouse input would map to the normally-headless machine), and fired off a DCC command to the monitor to change its input. The same script ran with a different argument would switch back to the normal display/control configuration. This solution worked pretty well until I was able to retire the headless machine early this year.
Re: Two computers, one monitor, zero fiddling (2025)
#13This is great. The Holy Grail of work/personal computing setups IMO. Too bad it’s so expensive.
I wish a KVM switch was a standard component of normal priced monitors these days. Especially one that also routed through all your peripherals, speakers, and everything.
Re: Two computers, one monitor, zero fiddling (2025)
#14I have a few boxes that I switch between, but for some software it's nicer that my "main machine" be on DVI, and everything else HDMI. I may have to look at some scripting option where if the keyboard / mouse disappear (KVM switched away) change the display to use the HDMI input.
I do worry that would just add more trouble / race conditions / issues around this stuff. I feel like nvidia + linux + monitors doing anything other than staying on + attached all the time causes some headaches.
Re: Two computers, one monitor, zero fiddling (2025)
#15It never occurred to me that you can send commands across DDC to your monitor. Binding that to a key on the keyboard in different OSs to trigger the monitor's built in KVM is a nice touch. I only change between my computers a couple times a day else I'd be setting this up this evening
Re: Two computers, one monitor, zero fiddling (2025)
#16FYI that if you have the right kind of Dell monitor, you can download their Display Manager software to do the same thing (and more): https://www.dell.com/en-us/lp/ddpm
Re: Two computers, one monitor, zero fiddling (2025)
#17Earlier quoted context omitted.
He bought a $900 monitor that has a KVM built in
Yeah, I read the whole article looking for any meat in there and there is none. I played with different setups as I, too, use both macos and linux. I remember doing a two screen setup where if you move the mouse to the edge of the linux screen, it appears on the macos one. I guess everything old is new again?
A two screen setup is not a one screen setup. I have a two screen mouse-edge setup and I was still interested to learn about being able to use a keyboard shortcut to control a monitor with a built-in KVM to switch between two computers on the same screen. That is, in fact, new to me.
Re: Two computers, one monitor, zero fiddling (2025)
#18If you turn one computer display off as in "xrandr --output DVI-D-0 --off", the monitor automatically selects some other computer to display.
Thus I have 2 computers and 3 displays, and I can do sentences like "displays 13", which uses only displays 1 and 3 and sends ssh-command "displays 2" to the other computer.
Re: Two computers, one monitor, zero fiddling (2025)
#19What a great idea. It should be obvious and easy but DDC commands are hard to find and should be documented better.
I have a Dell U4323QE in the office and look forward to trying this out. I wondered if it was the same DDC commands so I googled a little and found this gist (concerning DDM):
https://gist.github.com/nebriv/cb934a3b702346c5988f2aba5ee39...
Which has the very useful comment:
https://gist.github.com/nebriv/cb934a3b702346c5988f2aba5ee39...
Which states:
#define LUMINANCE 0x10 #define CONTRAST 0x12 #define VOLUME 0x62 #define MUTE 0x8D #define PBP 0xE9 #define SWAP_USB 0xE7 #define SWAP_INPUT 0xE5 #define INPUT 0x60 #define SUB_INPUT 0xE8 #define INPUT_ALT 0xF4 // alternate address, used for LG exclusively? #define STANDBY 0xD6
I much prefer simple DDC commands over using something like Synergy or Barrier. I think it is a much cleaner solution.
Re: Two computers, one monitor, zero fiddling (2025)
#20Yeah, this all sounds good in theory, but there's a lot of edge cases. For example, for me switching between Mac and Linux what often happens is that Linux just for some reason the it turns off the monitor port and it's black until I reboot and there was no easy way to get it back. This is while using fancy Dell monitors built-in KVM. Ultimately, I have settled on remote desktops as a more viable and quicker option.