5 ms·

Are there any KVM switches that do Displayport well (i.e. where switching between inputs does not look like a display disconnect to the PC)? I'm still using HD

by tivert 3y ago

Are there any KVM switches that do Displayport well (i.e. where switching between inputs does not look like a display disconnect to the PC)? I'm still using HDMI because I like to share my home multi-monitor setup between my personal machine and my work laptop, and the KVM switches are able to fool the PCs into thinking the monitor are always connected. Years ago I tried a Displayport switch, but it could not -- I assume because if the greater sophistication of the Displayport protocol.

mvid 3y ago
https://store.level1techs.com/?category=Hardware https://store.level1techs.com/?category=Hardware This is what I use. It appears to disconnect, but also doesnt seem to be an issue. My machines re-organize instantly.
- formerly_proven 3y ago
  It's gotten better in the last year or so with Windows 10 but it'll still sometimes just fall apart when the display configuration changes, which is something that just never happened for any reason with HDMI/DVI.
- zerkten 3y ago
  I was looking at this as an upgrade pick and don't have any re-arrangement with my TESmart (TES-HDK0402A1U-USBK). What monitor(s) do you have?
- jamestanderson 3y ago
  I got their 10gbps displayport switch to use with switching a single monitor between a Windows desktop PC and an M1 MacBook Pro. I have a 4k@144hz monitor and can get the full framerate and resolution with this setup. I've never had any problems, would highly recommend.
  - c-hendricks 3y ago
    Nice, I'll check these out. I went with an HDMI KVM and am worried about updates to HDMI making it obsolete.
xxpor 3y ago
The magic words you're looking for are "EDID emulation". The KVM will continue to send the EDID data from the monitor even after you've switched away, which will fix that issue. It's relatively uncommon and not always implemented super well, but it's a requirement for any DP KVM to be not super annoying IMO. There was one particular KVM brand that was supposed to do it well whose name is escaping me now :/. I was looking at buying one in ~ May 2020 for obvious reasons, but they were on super-backorder (also for obvious reasons), so I never got around to it. IIRC they were about $500 for a 4 input/2 output version, so not cheap.
- Fnoord 3y ago
  BliKVM PCIe I bought (based on PiKVM) came with an EDID emulator.
  - 111111IIIIIII 3y ago
    Too bad it doesn't support higher resolutions.
- hazebooth 3y ago
  Were you thinking of Level1techs? https://store.level1techs.com/products/14-kvm-switch-triple-monitor-2computer https://store.level1techs.com/products/14-kvm-switch-triple-...
  - xxpor 3y ago
    I'm 90% sure it was, but it looks like they did a major UI update to the site so it's not triggering the "that was it!" lightbulb in my brain.
    - AlotOfReading 3y ago
      I use one, so I can confirm they work extremely well, subject to some caveats: * The total cable length is important, both between the host / KVM and the KVM / monitor, as well as any daisy chained displays you have. I had to use certified cables to get everything working reliably with my setup. * There's a weird interaction with BIOS power on. The boot display drivers I have freak out if they aren't the active display and fail. I solve this by switching the KVM before I turn the computer on. After everything is booted into an OS, it works fine to switch. * Power supply quality is important. I had some issues before I made sure the power supply was reliable. KVM switches are just inherently difficult little devices. I haven't had issues since I got it working though.
jchw 3y ago
None of them are perfect, but I've heard good things about the DP switch from Level1techs. The thing is, all of them are a little tricky, but they mostly differ in how quirky they are, and I suspect the reason why people like the Level1techs DP switch is that they seem to at least try to alleviate some of the issues DP switches tend to get into. https://store.level1techs.com/products/14-kvm-switch-dual-monitor-2computer https://store.level1techs.com/products/14-kvm-switch-dual-mo... The startech one I have is alright... But Apple computers absolutely hate it and frequently refuse to display, and sometimes Windows gets stuck and USB devices stop working. Strangely enough... Linux doesn't ever have any problems with either display or input. A rare win, but fine by me.
- pxc 3y ago
  The Level1Techs KVM switches are rebranded Startech switches with 'dumber' firmwares whose dumbness affords better compatibility with niche DisplayPort features. I have a bunch of them and I like them pretty well, but getting a bunch of computers all plugged in turns out to be a bit of a nightmare, especially when you need some long-ish cable runs or you are daisy-chaining devices (e.g., multiple KVM switches, adding USB hubs or Thunderbolt docks, etc.). The Level1Techs KVM switches don't meet GP's criterion for hotplugging behavior, unfortunately. Switching between devices is just an unplug and replug for them. Like you, I've found that macOS and Windows don't handle hotplugging monitors well, but Linux desktops (in my case, KDE Plasma) consistently do the right thing and don't require a repeater to lie to them about monitors always being plugged in. FWIW, I don't get the 'Apple computers just refuse to work' issue with any of my L1T KVMs.
  - ender341341 3y ago
    > FWIW, I don't get the 'Apple computers just refuse to work' issue with any of my L1T KVMs. My work intel macbook worked great on it for like a year once I got a high quality usb-c -> displayport cable, but an os update borked it... though it's definitely the mac that's the problem as it also has problems sometimes with just strait to the monitor too (on the other hand 49" ultrawide is pushing the bandwidth near it's limits). My personal arm macbook has always worked great on it with even a crappy usb-c -> displayport my windows desktop also always worked great on it.
seanalltogether 3y ago
Can you explain why this is beneficial? I have a mac laptop and pc desktop at home that i switch between depending on whatever I need to do. By triggering a disconnect, it means all my mac windows that are on the main monitor will zip back over to the laptop so they're still reachable if i need to access them with the trackpad and integrated keyboard. When I switch the kvm back to mac all those windows jump back to the main monitor.
- pavon 3y ago
  Flaky drivers. KVM induced unresponsiveness is pretty much the only reason I ever have to hardboot my computers. Also, even if the drivers are solid, they take longer to renegotiate with a monitor that was removed and plugged back in compared to one they think was always there, which matters if you switch back and forth frequently. Lastly, sometimes the OS doesn't put things back they way they were when you plug a monitor back in. If you have a laptop which has a lower resolution display than the external monitor, you'll often return to find all the windows shrunk to fit the laptop display. Not an issue if you run everything full-screen, but annoying if you tile windows.
bbatha 3y ago
I had the startech one the siblings have mentioned but that wasn't very good and didn't do EDID emulation correctly. This CKL one [0] has been working really well, and supports USB 3 which is a nice bonus so I can share my webcam. Though sometimes after wake up my macbook forgets about my second monitor (I have an M1 connected to a cable matters thunderbolt dock), my windows machine which has direct DP connections doesn't have the same issue. 0: https://www.amazon.com/gp/product/B09STVW821/ https://www.amazon.com/gp/product/B09STVW821/
stephenr 3y ago
The new Dell 6K has kvm (and PiP) functionality across its inputs, and it does appear from my modest use of this feature so far, that it works as you would want (ie it still thinks the display is connected, even when not showing that input)
- 111111IIIIIII 3y ago
  I would prefer that with 1 display but I have 2 Dell 6Ks and it's kind of annoying if I want to have them each on a different PC. (I use a usb switch to switch my peripherals between displays)
nyanpasu64 3y ago
Never mind KVM switches, I wish powering off my DP monitor while leaving wall AC power plugged in didn't appear as a display disconnect to the computer.
m463 3y ago
I don't think I've had a KVM switch work well since VGA+PS/2 They all try to be too smart. As a matter of fact, I usually use a monitor switch of some sort, then use mechanical USB switches - one for keyboard, one for mouse. That seems to be the only way to get mouse and keyboard to work well (basically just a hardware connection, no smarts)
smitty1110 3y ago
Belkin makes some, up to duplex 4k@60hz, but holy mother of god are they expensive.
- nine_k 3y ago
  Look how expensive are the chips they are using. High-speed, high-bandwidth, low-delay interfaces are apparently hard.

by tivert 3y ago

mvid 3y ago

https://store.level1techs.com/?category=Hardware https://store.level1techs.com/?category=Hardware This is what I use. It appears to disconnect, but also doesnt seem to be an issue. My machines re-organize instantly.

formerly_proven 3y ago
It's gotten better in the last year or so with Windows 10 but it'll still sometimes just fall apart when the display configuration changes, which is something that just never happened for any reason with HDMI/DVI.
zerkten 3y ago
I was looking at this as an upgrade pick and don't have any re-arrangement with my TESmart (TES-HDK0402A1U-USBK). What monitor(s) do you have?
jamestanderson 3y ago
I got their 10gbps displayport switch to use with switching a single monitor between a Windows desktop PC and an M1 MacBook Pro. I have a 4k@144hz monitor and can get the full framerate and resolution with this setup. I've never had any problems, would highly recommend.
- c-hendricks 3y ago
  Nice, I'll check these out. I went with an HDMI KVM and am worried about updates to HDMI making it obsolete.

xxpor 3y ago

The magic words you're looking for are "EDID emulation". The KVM will continue to send the EDID data from the monitor even after you've switched away, which will fix that issue. It's relatively uncommon and not always implemented super well, but it's a requirement for any DP KVM to be not super annoying IMO. There was one particular KVM brand that was supposed to do it well whose name is escaping me now :/. I was looking at buying one in ~ May 2020 for obvious reasons, but they were on super-backorder (also for obvious reasons), so I never got around to it. IIRC they were about $500 for a 4 input/2 output version, so not cheap.

Fnoord 3y ago
BliKVM PCIe I bought (based on PiKVM) came with an EDID emulator.
- 111111IIIIIII 3y ago
  Too bad it doesn't support higher resolutions.
hazebooth 3y ago
Were you thinking of Level1techs? https://store.level1techs.com/products/14-kvm-switch-triple-monitor-2computer https://store.level1techs.com/products/14-kvm-switch-triple-...
- xxpor 3y ago
  I'm 90% sure it was, but it looks like they did a major UI update to the site so it's not triggering the "that was it!" lightbulb in my brain.
  - AlotOfReading 3y ago
    I use one, so I can confirm they work extremely well, subject to some caveats: * The total cable length is important, both between the host / KVM and the KVM / monitor, as well as any daisy chained displays you have. I had to use certified cables to get everything working reliably with my setup. * There's a weird interaction with BIOS power on. The boot display drivers I have freak out if they aren't the active display and fail. I solve this by switching the KVM before I turn the computer on. After everything is booted into an OS, it works fine to switch. * Power supply quality is important. I had some issues before I made sure the power supply was reliable. KVM switches are just inherently difficult little devices. I haven't had issues since I got it working though.

jchw 3y ago

None of them are perfect, but I've heard good things about the DP switch from Level1techs. The thing is, all of them are a little tricky, but they mostly differ in how quirky they are, and I suspect the reason why people like the Level1techs DP switch is that they seem to at least try to alleviate some of the issues DP switches tend to get into. https://store.level1techs.com/products/14-kvm-switch-dual-monitor-2computer https://store.level1techs.com/products/14-kvm-switch-dual-mo... The startech one I have is alright... But Apple computers absolutely hate it and frequently refuse to display, and sometimes Windows gets stuck and USB devices stop working. Strangely enough... Linux doesn't ever have any problems with either display or input. A rare win, but fine by me.

pxc 3y ago
The Level1Techs KVM switches are rebranded Startech switches with 'dumber' firmwares whose dumbness affords better compatibility with niche DisplayPort features. I have a bunch of them and I like them pretty well, but getting a bunch of computers all plugged in turns out to be a bit of a nightmare, especially when you need some long-ish cable runs or you are daisy-chaining devices (e.g., multiple KVM switches, adding USB hubs or Thunderbolt docks, etc.). The Level1Techs KVM switches don't meet GP's criterion for hotplugging behavior, unfortunately. Switching between devices is just an unplug and replug for them. Like you, I've found that macOS and Windows don't handle hotplugging monitors well, but Linux desktops (in my case, KDE Plasma) consistently do the right thing and don't require a repeater to lie to them about monitors always being plugged in. FWIW, I don't get the 'Apple computers just refuse to work' issue with any of my L1T KVMs.
- ender341341 3y ago
  > FWIW, I don't get the 'Apple computers just refuse to work' issue with any of my L1T KVMs. My work intel macbook worked great on it for like a year once I got a high quality usb-c -> displayport cable, but an os update borked it... though it's definitely the mac that's the problem as it also has problems sometimes with just strait to the monitor too (on the other hand 49" ultrawide is pushing the bandwidth near it's limits). My personal arm macbook has always worked great on it with even a crappy usb-c -> displayport my windows desktop also always worked great on it.

seanalltogether 3y ago

Can you explain why this is beneficial? I have a mac laptop and pc desktop at home that i switch between depending on whatever I need to do. By triggering a disconnect, it means all my mac windows that are on the main monitor will zip back over to the laptop so they're still reachable if i need to access them with the trackpad and integrated keyboard. When I switch the kvm back to mac all those windows jump back to the main monitor.

pavon 3y ago
Flaky drivers. KVM induced unresponsiveness is pretty much the only reason I ever have to hardboot my computers. Also, even if the drivers are solid, they take longer to renegotiate with a monitor that was removed and plugged back in compared to one they think was always there, which matters if you switch back and forth frequently. Lastly, sometimes the OS doesn't put things back they way they were when you plug a monitor back in. If you have a laptop which has a lower resolution display than the external monitor, you'll often return to find all the windows shrunk to fit the laptop display. Not an issue if you run everything full-screen, but annoying if you tile windows.

bbatha 3y ago

I had the startech one the siblings have mentioned but that wasn't very good and didn't do EDID emulation correctly. This CKL one [0] has been working really well, and supports USB 3 which is a nice bonus so I can share my webcam. Though sometimes after wake up my macbook forgets about my second monitor (I have an M1 connected to a cable matters thunderbolt dock), my windows machine which has direct DP connections doesn't have the same issue. 0: https://www.amazon.com/gp/product/B09STVW821/ https://www.amazon.com/gp/product/B09STVW821/

stephenr 3y ago

The new Dell 6K has kvm (and PiP) functionality across its inputs, and it does appear from my modest use of this feature so far, that it works as you would want (ie it still thinks the display is connected, even when not showing that input)

111111IIIIIII 3y ago
I would prefer that with 1 display but I have 2 Dell 6Ks and it's kind of annoying if I want to have them each on a different PC. (I use a usb switch to switch my peripherals between displays)

nyanpasu64 3y ago

Never mind KVM switches, I wish powering off my DP monitor while leaving wall AC power plugged in didn't appear as a display disconnect to the computer.

m463 3y ago

I don't think I've had a KVM switch work well since VGA+PS/2 They all try to be too smart. As a matter of fact, I usually use a monitor switch of some sort, then use mechanical USB switches - one for keyboard, one for mouse. That seems to be the only way to get mouse and keyboard to work well (basically just a hardware connection, no smarts)

smitty1110 3y ago

Belkin makes some, up to duplex 4k@60hz, but holy mother of god are they expensive.

nine_k 3y ago
Look how expensive are the chips they are using. High-speed, high-bandwidth, low-delay interfaces are apparently hard.