I recently bought an expensive KVM switch from a different vendor which states to support DP1.4, persistent EDID, etc… Sadly I’m having a whole bunch of problems (especially with a MBP M2 and my keyboard).
Even tho I can’t refund the switch, I’m still wondering, if it might be worth getting the L1T KVM. Maybe you can give me a recommendation if it will work better with my setup:
Screen 1: Asus ROG PG279Q (1440p @ 144/165Hz)
Screen 2: Asus BE27A (1440p @ 60Hz)
Screen 3: Asus BE27A (1440p @ 60Hz) [this one is always connected directly to the Windows system]
PC 1: Windows Desktop (Nvidia GeForce 3080Ti GPU)
PC 2: MacBook Pro M2 Pro (only supports 2 screens, I know)
HID: Corsair K96 RGB [does not work at all with my current KVM when using the DDM/HID ports; works on the normal USB3 port, but KVM hotkeys won’t work]
HID: Roccat Kone Aimo
USB: Logitec Brio Webcam [has problems with my current KVM on Windows; works fine on MacOS]
USB: External USB Sound System (Teufel)
The main problem I’m currently having is that the MBP M2 randomly does not recognizes the displays anymore. This always happens after it being asleep for more than a couple of minutes. Disabling sleep prevents that issue, but I don’t want the system to be running 24/7 in a home office setup. And even without sleep, one of the screens occasionally is not detected when switching channels on the KVM switch.
Is this something that is confirmed to work with the L1T KVM switch?
As the L1T KVM does not provide built in EDID emulation, I will probably have to buy additional hardware. I saw that L1T offers a DP Repeater for that purpose, but it’s only DP 1.2. Would that still work for my 1440p @ 144Hz screen? Would using such device might cause other problems with e.g. HDCP content, GSync, etc.? Or do you have a recommendation for a DP 1.4 EDID emulator that works in headless mode in combination with the L1T KVM?
Edit: Some additional questions:
Is the 3,5 audio jack a 3-pole or 4-pole one? Does it support both - microphone and headphones in one cable?
Is there an estimated date for the 3-screen KVM with the 10Gbps USB to be back in stock?
Don’t think a kvm is for you. corsair can’t work as hid is a standard and the Corsair keyboard is only hid when it’s in bios mode. Can’t sniff the protocol of some crazy moon language for the shortcuts. Otherwise works fine on ours.
You could get the kvm for thin clients with build in emulation but lose proper freesync/gsync compatibility. 1440p/120hz is otherwise fine there.
The Mac thing you’d probably need a caldigit dock? Since it’s a mac with 3 displays is it a displaylink dock for display 3? If displaylink drivers are installed but old that might be the Mac issue.
Audio is 3 pole. I recommend a USB dac instead anyway go avoid analog ground loop problems.
Apple is hard on kvm users usually. Recently had a customer where the Mac always sleeps even if it’s set not to and the whole Mac won’t wake up when switching to it. But it will sleep and wake fine if the lids open. It goes to coma if closed tho. Just Mac things. Apple doesn’t care.
Otherwise haven’t had any reports of m2 displays disappearing. Usually that kind of thing is USBC to dp adapters though.
Hi @wendell, thanks a lot for taking the time to answer me!
Hah! Already suspected they are doing some non-HID-compliant stuff. I’m currently using it in BIOS mode, but not sure what it does to my polling-rate (this as well disables most non-standard hotkeys, so… meh). Do you by any chance know if [Das Keyboard 6 Professional Mechanical Keyboard] is HID complaint? Or do you have a list of mechanical keyboards (with cherry switches in the best case) that are working fine in the HID ports?
Is that always the case with EDID emulation? My current KVM switch at least claims to support freesync/gsync, but I admit I haven’t tested it yet.
In the description of the thin client KVM you recommend software support instead. macOS for sure does not implement something like that natively, but I did some tests with Windows 11: Disconnecting one of the secondary screens works super nicely (no windows moved arround), but as soon as I disconnect the “main” screen, Windows chooses one of the other displays to be the “main” screen and moves all windows to this one (and doesn’t automatically restores them when I reconnect the former “main” screen). Is that happening with the L1T KVM switch as well?
I’m not really used to macOS and the Mac ecosystem (just got the machine from my new employer). I’m fine with using just 2 displays, but I had the same problems like your customer. The only way to prevent sleep is a specific terminal command - but this is not what I want either.
These are the adapters I’m currently using:
But I even had a different one previously, which did not work as well. So not sure, if in this case it’s a USB-C-to-DP problem or just caused by the KVM EDID emulation.
QMK-based keyboards are generally pretty fabulous. If you can disable nkey rollover (because one keyboard shows up as lots of keyboards in that case) then those have a better shot at working.
yeah, you can lie that its working but when you look at it on the high speed, something doesn’t look right to me. It can work in some scenarios but… you open yourself up to lots of bizzaroland behavior.
windows didnt either for a long time – persistent windows was a software crutch. I think there are some app like this for macos but I’m not sure what they are or how well they work.
yeah so when you use windows, you have to disconnect all the displays, not just some of them. I think this situation is also pretty bad even when you have monitor emulation. Things can open on a monitor you can’t actually see and you’re left scratching your head.
if you only switch some and not all of your monitors, that’s how windows is designed. Tough to fix that in any kvm…
the problem wasn’t so much the sleep, it was the wakeup. It was waking up fine, taking them back to the login screen, everything worked. But they didn’t want the login screen and that was disabled in the gui. but even disabling sleep via cli and gui it would still sleep
doesn’t matter if it uses the same chipset. We recommend moshi for this reason. Caldigit has some double DP out TB docks that also charge and work well if you’re running a resolution of less than 2*4k/60.
edid emulation does bring a whole new set of possible bugs. I wish apple would actually test things to stnadards a little more… they still dont properly support DSC unless you have one of their fancy pants LG 5k monitors. It’s a whitelist basically.
Thanks again for your detailed answer @wendell! Very much appreciated.
Interesting. Didn’t know about this QMK framework and the implications of using it. Was always wondering what adds 4 HID keyboards to my device manager
I can imagine. Guess I have to try it out and see if it works for me or not. My “technical brain” definitely likes a passthrough KVM like yours way better than complex EDID emulation stuff. I really hate that big OS are still that bad when it comes to multi display support. There should be a way to change the default behavior when it comes to window positioning and screen plug’n’play.
Makes sense. Thanks for that bit → that tells me to buy a 3 port L1T KVM and not the 2 port one, if I choose to go that route.
True, but that can easily be fixed by quickly switching back to the system (if you notice it ). In my case I was using that 3rd display to monitor some stuff on my personal system while still working on the company laptop. This on the other hand is probably a big waste of power anyways (running a Sapphire Rapids workstation that easily draws 300W while idling…). It’s probably better to build me a tiny Raspi system for monitoring purposes.
Do you have experience with the 3D CAC-1557 as well? This is what the support of the other KVM brand recommended to me right now. Will give it a shot, but if that does not work as well, I’m definitely going for one of your KVMs.
Bad tongues would say they are doing that on purpose…
@wendell I could not wait for the 3 screen KVM, so I ordered the 4 screen one instead (a little bit capacity for extension never hurts )
Just want to say thank you for this great product!
So far, monitor detection works perfectly fine on the MBP (had huge issues here with the previous KVM), the USB devices do switch perfectly fine as well (especially had trouble with my Logitech Brio Webcam which now works like a charm).
). In my case I was using that 3rd display to monitor some stuff on my personal system while still working on the company laptop. This on the other hand is probably a big waste of power anyways (running a Sapphire Rapids workstation that easily draws 300W while idling…). It’s probably better to build me a tiny Raspi system for monitoring purposes.