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Comment by gizmo | Hacker News Reader

Good KVMs, specifically the ones from Level1Tech[1], are smart enough to keep all monitors connected virtually so all your windows stay in place when you switch back and forth between machines. There is no delay of plugging devices in because from the perspective of the client PCs the USB/display port devices were never gone. Of course you can connect a bunch of peripherals to a dock and switch the upstream thunderbolt connection, but that doesn't work correctly.

Crappy KVM solutions are easy. Good ones are hard.

[1] https://www.store.level1techs.com/products/hardware (no affiliation)

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I bought the Level1Tech KVM and they do no support EDID emulation. I switch between a Mac and a Linux box (Gnome):

- Mac goes to sleep

- Gnome will default back the default monitor configuration and move the windows around

They do have a 1.2 DP KVM with EDID emulation, but you loose all the benefits of the 1.4 DP.

Its all on their FAQ forums

https://forum.level1techs.com/t/official-l1techs-kvm-faq-ult...

Rextron (the OEM behind Level1Techs' kVMs) has a version with EDID emulation, but it only supports usb1.1, not 3.0 or above. I sent a casual question to their contact to see what getting a branded one looks like and the Level1Techs ones are not sold at a huge markup, only about 20% or so.

EDID emulation done right is expensive.

Do you know of any solid KVMs with EDID emulation and 1.4 DP?

Yeap! This is my setup for MacOS and Linux with display port: KVM Switch Dual Monitor DisplayPort 1.4 8K@30Hz 4K@144Hz 2 in 2 Out,DP1.4 KVM Switch and 4 USB3.0 for 2 Computers,Backnward Compatible DP1.2 with DP+UBS Cables and Wired Controller https://a.co/d/5A3IG5P

Under the Extend mode, it says it requires dual-graphics card. What does that mean? Guessing it's an odd translation.

I think it just means if you want to kvm with two monitors over DP you need two DP ports on each computer.

yeap, this is how my setup is. Two DP ports are occupied.

The only ones I know of are the ConnectPRO ones. I have a UDP2-14AP, but it's really finicky. It works great with some systems and monitors, even at high resolutions and refresh rates. But other systems (for me, my MacBook) involve several blank-and-move-all-your-windows-around cycles before it settles and becomes usable after switching to it. I suspect this might be a monitor compatibility thing with the Mac, but I'm not sure.

Anyway, it's pricey and picky about compatibility, so it's hard to recommend, but I'm not aware of anything comparable in terms EDID emulation and support for high res/refresh modes.

Edit: Based on a sibling comment, the situation may have changed and there may be comparable ones around!

Replying to follow (idk if there is a way to follow a thread). I have an Apple Display and would need 1.4 DP

You can "favorite" a comment and then access your favorite comments from your profile. Replying to a comment with a noop just to "follow" it lowers the snr for everyone else.

To favorite the comment click on the time the comment was posted and then on the following page click favorite.

TIL, thanks. I think they should make that doable in one click, though.

Most newer Dell monitors have built -in KVMs and hubs. It's nice, becuase with wireless peripherals that USB receivers, it's a cableless setup. With a laptop, it's just a single cable to hookup everything.

Bought one such monitor.

2 years later switched from m1 to m2 and it no longer works well enough (may also be the Sonoma upgrade stil gotta verify that). The devices get disconnected and glitch etc.

Went to check with dell and monitor is "not supported" on macos.

I am at a loss for words.

I have an Intel Macbook 2019 for work. I've tried a couple different kvm solutions but they all had issues, always on the Mac side. The best I got was <1 sec switching from Mac to Linux and 10-15 seconds switching from Linux to Mac for everything to stabilize.

I ended up going with the nuclear option of an IP KVM https://www.raritan.com/support/product/dominion-kx-iv-101 that will do all the resolutions I want at 60hz. It was very expensive, but on the bright side it lets me keep work laptops completely unmodified and easily swappable.

How about “apple get your act together with those m2s”? :)

Disclaimer: meant to be humorous.

macOS has either always lacked (like Display port MST) or later broken/crippled (like DisplayLink support) some important features for multi-monitor setups. I wonder if those things or similar things are somehow implicated in these KVM-enabled monitors.

I also had hell even with an Intel Macbook Pro. This whole just works thing Apple has been able to project is unfortunate. I have refused using Apple products from work because of how poorly their products integrate. It's not Dell. It's Apple. Any other monitor manufacturer will have the same issues.

Apple also refuses to implement a protocol that allows controlling the brightness and volume of a non-Apple monitor from the keyboard or even macOS itself. It's infuriating. The only monitors it works with are Apple's and the two overpriced Apple-sanctioned LG monitors sold in the Apple Store.

I've had good luck with the Lunar app - it manages my Dell and LG monitors on an M2. (No affiliation) https://lunar.fyi

I use an app called MonitorControl on a M1 16" MBP running Sonoma that adjusts both the MBP screen and external HP 25f monitor. It adjusts the brightness and contrast of whichever screen the cursor is in.

Right, but that's part of the point. Apple should just have this inside macOS.

From MonitorControl's GitHub README, emphasis mine:

> Most modern LCD displays from all major manufacturers supported implemented DDC/CI protocol via USB-C, DisplayPort, HDMI, DVI or VGA to allow for hardware backlight and volume control.

And a blog entry by the author of Lunar, an app mentioned elsewhere for this problem: https://alinpanaitiu.com/blog/journey-to-ddc-on-m1-macs/

These are not examples of "just works". Apple intentionally does these things to cripple integration into non-Apple products.

This kind of whining is basically trolling. 'I've tried nothing and I'm angry it doesn't work!'

A 16" Macbook Pro starts at $2,499. I do expect it to just work with basic peripherals and protocols for them.

I'm just explaining how it doesn't just work, and that I'm perfectly happy not using their products. My comment was also a correction that it's on Apple, and not Dell, as to why Apple products don't work well with non-Apple devices. This is a tactic that Apple uses to try and denigrate non-Apple products and get people to come back to Apple's "premium" versions of those products.

There are clear and easy steps Apple could take, but they won't.

"I don't want to tinker with anything and have everything work out of the box" is Apple's entire value proposition.

That's the one justification that consistently gets upvoted to the top any time someone questions Apple's pricing structure. Please don't change the tune when someone reports a serious ongoing problem.

I'm a little interested in one of these as an option to eventually replace my Dell WD19 USB-C DP-alt mode dock for my Dell notebook and my Desktop PC which connects by HDMI cables.

One question I couldn't see an answer to is whether or not the I can make the network port "sticky" to my Dell notebook (plugged in over USB-C), or will it "move" to my Desktop PC when I switch to it?

I read last year how recent standard made higher wattage delivery over USB-C now standard (I think it was the latest Thunderbolt one), so I'm waiting until these monitors can do that.

Also got the Level1Tech one last year, very expensive but worth it imho. I use it to switch between my work and home PC many times a day, and it has worked flawlessly so far with two monitors (4k60hz+2k144hz) using Linux on both machines. USB audio, mic, 4k camera, printer and keyboard+mouse peripherals

How is the latency with these devices? I produce music as a hobby and have many connections to deal with and as low latency as possible is ideal. I am looking for something I can switch between 3 different devices basically. Work laptop, MacBook Pro, and custom Linux PC. The 2 latter ones I produce on. Would this device work for that?

I haven't noticed any additional latency, but my workload isn't particularly latency critical (I do sometimes game in the 144hz display and it's as smooth as it was before I got the KVM). They don't have a 3-computer version afaik so you'd need to go with this one probably: https://www.store.level1techs.com/products/p/14-display-port...

The added latency, if any, is not noticeable on 120-160Hz monitors. The KVM isn't doing any processing.

The windows not staying in place bug only occurs with crappy window managers. Decent ones are smart enough to put the windows back where they were when the monitors come back.

I have had great success with a generic KVM I found on amzn [0], but it now appears to be unavailable, which is a shame because I wanted to buy another. Perhaps I can find it somewhere else. It has never failed to switch between sources and the only delay, as some others are pointing out, is the HDMI handshake process inherent to the monitors themselves.

I did have a considerably more expensive TESmart [1] but couldn't use it because it had some weird incompatibility between it, thunderbolt docking station [2] I used with it (which also work flawlessly), and the MBPs connected to it. I could never figure out why, even raising the issue to support with no luck.

My two cents.

[0] https://www.amazon.com/gp/product/B088WGKFZH

[1] https://www.amazon.com/gp/product/B08N494N7X

[2] https://www.amazon.com/gp/product/B08HR3T837

You don't feel skeptical of products from a company called "GREATHTEK-More Convenient"? I am far too paranoid to plug random technology like that into my computers. It makes shopping for such things on Amazon nearly impossible.

What could they do hypothetically? They don't have network access to phone home, do they?

PWAY Brand. Seems to be available on Aliexpress. just FYI

For HDMI you have lots of options that provide EDID emulation. For DP there's only one game in town and it costs more than most computers.

Given that GPU cards tend to have more DP ports than HDMI ports, why might that be? Why don't makers of KVM switches follow the same preference as GPU's do? (or vice versa. Why do we have two standards anyway)

> Crappy KVM solutions are easy. Good ones are hard.

In this case what's crappy is those desktops rearranging windows when you turn off a monitor. I'd rather have my PC not know whether a monitor is connected or not, like used to be with vga.

VGA always had means for detecting a monitor. Originally, a vga monitor would pull down at least one of the id pins, and edid replaced that.

A lot of software didn't really care and just sent signals into the void, but it's possible to do that with DVI or DP, too.

I really want one but I just can't justify paying like 800-900€ for a dual-monitor four-computer one when I have a USB switcher and can just switch inputs on my monitors.

I came to this conclusion myself recently. I have the Cable Matters 4 port USB switch and it works just fine for my purposes.

https://www.amazon.com/dp/B083JKDNRJ

I was hopeful and tried using this Monoprice KVM switch (linked below), but it just wasn't worth it in my experience. Despite supporting Display Port 1.4, I could not use my monitor to its full ability with my PC (3440x1400 @165Hz w/ 10 bit color). Dropping the connection when switching inputs was also incredibly annoying; every time I switched away from my Macbook it would go to sleep.

https://www.amazon.com/dp/B093N1DR8Y

I'm happy to switch inputs on both the USB switch and my monitor separately because it's not actually too large of a hassle, and the monitor doesn't "disconnect" when switching video inputs on my monitor so my Macbook doesn't immediately go to sleep.

If anyone is in the market for a KVM switch, consider a USB hub first. You might find yourself satisfied. They're much less of a hassle and cost very little in comparison to a full featured KVM switch.

Big+1 to the level 1 techs kvm. Ive had a little over a year and it's flawless.

2 2.5k/1440p monitors both 144hz and it switches every time. Highly recommend. Albeit a bit pricey.

Does that impact the time how long the monitor takes from switching between display off and showing something on the screen?

You still have to do a handshake (determine resolution, refresh rate, etc) before you get a picture, and that takes maybe 3 seconds. Some monitors can handshake a bit faster, but not by much.

Still faster than my monitor. It can take long enough to turn on that my laptop goes to sleep (from the password entry screen). And since I'm using the monitor as the KVM, I can't even mash the keyboard to keep it awake, I got to reach over and keep touching the laptop.

Couldn't you increase the time your laptop waits before going to sleep?

- https://askubuntu.com/questions/1042641/how-to-set-custom-lo...

- https://support.apple.com/guide/mac-help/set-sleep-and-wake-...

etc

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