Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Two computers, one monitor, zero fiddling (2025)

alexplescan.com

Post reply on HN
Print view View original

131–140 of 153 posts

Re: Two computers, one monitor, zero fiddling (2025)

#131

Post by ninalanyon »

zeta0134 wrote: post #125
tomaskafka wrote: post #124

I am trying to do the same, and I absolutely don't understand what is happening in the 3-5 seconds while two gigahertz-level machines and a modern monitor negotiate something over tens-gigabit-per-second connection. If Steve Jobs herded makers of all the parts into a single room, and told them they aren't leaving until this takes 10 ms, I would be immensely grateful and I bet it could be resolved in a week.

A pox specifically on my otherwise delightful samsung OLED, which immediately upon any sort of disconnect event (say, changing the resolution, or restarting the machine) decides to spend 10-15 seconds slow-scanning every other possible input. Exactly none of which have a physical cable attached, and exactly zero of which have ever been used once. What the devil is taking so long? I'm sure there's some technical reaso…

The technical reason is probably that doing it faster wasn't in the specification.

Re: Two computers, one monitor, zero fiddling (2025)

#132

Post by sobeston »

LiamPowell wrote: post #127
heatmiser wrote: post #56

I solved the multi-computer-to-multi-monitor problem with a Level1Techs KVM[1]. The price (~$500 for the variant I purchased) initially gave me pause, but the longer I've had it, the happier I am with my decision. It handles all the switching at the hardware level and thus has no perceptible lag for video or anything else. I'm able to connect a single set of peripherals, in my case, two monitors, a keyboard, a trackb…

When did KVM switches get so expensive? Level1Techs doesn't appear to be much more expensive than the competition, but the margin on all of these has to be absurd. They're not a particularly niche product and the BOM cost is only going to be $20 at most (a TMUXHS4612 is $1 for reference). I'm amazed that there's not more competition bringing the price down here.

Level1Techs' KVM products have always been expensive, and they're arguably the best around. There aren't many competing products.

Re: Two computers, one monitor, zero fiddling (2025)

#133

Post by teekert »

I have a Iiyama with build in hub, at first it seemed ideal, just plug everything into the monitor. But my mouse glitches when used through the hub (MX Master 3S), the internet cable is only available to the active computer (so no tasks requiring internet can run on the other computer).

All in all, I just use the USB-C to HDMI switch functionality and couple the computers to keyboard/mouse via bluetooth, plus I bought a switch for the ethernet. It's a shame it's so suboptimal.

Another minor annoyance is that when I turn off one computer and want to switch to the other, the display turns off, taking about 5-10 sec to do so. Then I manually turn it back on and it's ready in another 3 sec. So I do this thing where I hover about the turn-off button, hit it and immediately switch so the monitor won't turn off.

It's hard to make convenient tech it seems.

Re: Two computers, one monitor, zero fiddling (2025)

#134

Post by mrheosuper »

tomaskafka wrote: post #124

I am trying to do the same, and I absolutely don't understand what is happening in the 3-5 seconds while two gigahertz-level machines and a modern monitor negotiate something over tens-gigabit-per-second connection. If Steve Jobs herded makers of all the parts into a single room, and told them they aren't leaving until this takes 10 ms, I would be immensely grateful and I bet it could be resolved in a week.

Probably debouncing, when anything/any events happen, you have to ask yourself, did this event truly happens, or just some weird glitch and can safely ignore it.

Re: Two computers, one monitor, zero fiddling (2025)

#135

Post by gblargg »

m463 wrote: post #105
heatmiser wrote: post #56

I solved the multi-computer-to-multi-monitor problem with a Level1Techs KVM[1]. The price (~$500 for the variant I purchased) initially gave me pause, but the longer I've had it, the happier I am with my decision. It handles all the switching at the hardware level and thus has no perceptible lag for video or anything else. I'm able to connect a single set of peripherals, in my case, two monitors, a keyboard, a trackb…

kvm usb switching is always broken, sometimes subtly, sometimes obvious I use mechanical USB switches to individually switch USB lines like this: https://www.amazon.com/dp/B01I0Y3GEE one for keyboard, one for mouse Problems it avoids - cable speed usb - no extra latency - using boot-up hold-key-down sequences on macos works fine - keyboard doesn't get hung in weird states - no hotkey conflicts - no mouse gets in weir…

There are electronic versions of 2-1 switches that also just connect the data lines through, no hub, but use electronic switches rather than multi-pole mechanical switches (they naturally work bidirectionally, so you can switch a computer between two devices as well as one device between two computers).

Re: Two computers, one monitor, zero fiddling (2025)

#136

Post by gblargg »

KeplerBoy wrote: post #128
tomaskafka wrote: post #124

I am trying to do the same, and I absolutely don't understand what is happening in the 3-5 seconds while two gigahertz-level machines and a modern monitor negotiate something over tens-gigabit-per-second connection. If Steve Jobs herded makers of all the parts into a single room, and told them they aren't leaving until this takes 10 ms, I would be immensely grateful and I bet it could be resolved in a week.

Probably link training. The very fact that it is a tens-gigabit-per-second connection in an environment full of RF noise (we all love our high powered switching power supplies) makes it hard to get a reliable signal instantly. Still shouldn't take longer than a few hundred ms though (worst case).

The pretty generic TV I use a a monitor apparently keeps the links up with its three inputs, at least for a while after recent use, so switching between two powered computers is quick, about half a second. I started using that rather than a KVM since the KVM caused a retrain, adding several seconds to switching.

Re: Two computers, one monitor, zero fiddling (2025)

#137

Post by timonoko »

timonoko wrote: post #18

If 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.

How do you change display-modes with ssh?

  os.system(f'ssh -Y {compu2} "DISPLAY=:0; display.py {modes};"')

Re: Two computers, one monitor, zero fiddling (2025)

#138

Post by bni »

amiga386 wrote: post #47

With Windows and AutoHotkey and https://www.nirsoft.net/utils/control_my_monitor.html You can add this .ahk script to run at startup: ^F4:: Run C:\Users\YourNameHere\Documents\AutoHotkey\ControlMyMonitor /SwitchValue Primary 60 17 3 Return Where the file path is where you've put ControlMyMonitor.exe, "Primary" means the main Windows display, the "60" means input select, and the "17" and "3" are the values you observe…

Thank you precisely what I was looking for on the Windows side

Re: Two computers, one monitor, zero fiddling (2025)

#139

Post by BrokenCogs »

leosanchez wrote: post #116
BrokenCogs wrote: post #81

Wait why not just buy a usb switch? I switch between 4 computers using the same monitor, keyboard and mouse.

I have a USB switch for 2 computers. Which switch are you using for 4 computers?

This one: https://a.co/d/04gGroV2

Re: Two computers, one monitor, zero fiddling (2025)

#140

Post by criddell »

mbauman wrote: post #86
space_ghost wrote: post #12

I 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…

I loved synergy back in 2005 when it was _actually_ open source! It was probably my first open source contribution! But then it was enshittified and made impossible to build from source in order to support the commercial dreams.

The bottom tier is a one-time $15 purchase, the top tier is only $29. That doesn't seem all that evil...
Post reply on HN