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Comment by ardy42 | Hacker News Reader

> What KVMs instead contain is similar to the rescaler ASICs found in a monitor, they receive multiple streams of display data and mix/forward/scale one of these. But since they constantly receive all of the streams, switching can be instant, or at least as quick the monitor can modeswitch (which, for some reason, takes screens at least a second).

Do you know of a DisplayPort KVM switch that actually does that? I tried one a few years ago (it was one of the first ones I saw for a reasonable price), but I returned it immediately because I got the brain-dead window-rearranging behavior you described whenever I switched. I've been reluctant to try another until I know it solves that issue.

I still use one of these HDMI switches (https://www.iogear.com/product/GCS62HU/), because it's EDID support actually does make it transparent to the PCs, so I can switch instantly like I want to.

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ConnectPRO claims that their switches pass EDID information to all systems. They have some examples of it being in use in Youtube https://www.youtube.com/user/rexwu168/videos

I finally ordered one a while ago after I couldn't find anything cheaper with similar functionality, but it's currently on backorder so it will take some time to arrive & see how well it works in reality.

I have a ConnectPro UDP2-12AP, and can confirm that systems connected to it do not see the monitor go away on switch.

There is an interruption if you press the KVM reset button, but that's not something you should often do.

https://www.gdsys.de/en/kvm-solutions/kvm-switches/dp12-mux3... This is a switch that can switch video instantly when all source have the same resolution and refresh rate. But it's not really for the consumer market and therefore is quite expensive.

I haven't used them myself, but I've heard the KVM switches sold by level1tech don't trigger that.

A year ago, I considered their product...then I saw this commentary[1] straight from the cow's mouth:

> Most of the support on (their DisplayPort 1.2 KVM offering) have been down to bad or dodgy DisplayPort cables. Seriously, it's like sort of nuts. Like you go on Amazon, you order a DisplayPort cable, it doesn't work, and it's like, "Well, I have two DisplayPort cables that work independently, but when I plug both of them into the KVM, it doesn't work." The KVM doesn't have a repeater. So if you've got two 6-ft cables that pass through the KVM, it is like as if you have one 12-ft cable, and while one 6-ft cable might work, 1 12-ft cable will not because...(Jedi hand gestures)...repeater. So use good quality cables, you'll be fine.

Ignoring the "repeater" terminology wank, that soundbite disclosed enough about the white label device's internal architecture for me to infer with confidence that even if EDID was properly implemented (the easiest part), the video interface is skimp and doesn't actually buffer frames in realtime...which means that on switch, the monitor's receiving ASIC will detect frame interruption as it starts to receive its new stream and blank for a second or two while it tries to reacquire...which is definitely not the instantaneous performance I was looking for.

[1] https://youtu.be/0b0_yz-oDjQ?t=74

Damn...

I’m using a TESmart HDMI KVM that behaves well, at least with my monitors. My USB peripherals sometimes need a reset though.

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