L1 KVM issues

Boy oh boy am I having trouble with a brand new L1 KVM. My particular model is the PAAG-E3114B (4PC 1 Monitor).

My setup is as follows:

PC 1, single monitor via KVM
PC 2 one dedicated monitor, second monitor is shared with PC 1 via KVM.

PC #1 absolutely refuses to post when the KVM is connected via USB. I have tried multiple USB ports and multiple cables. Once I unplug the KVM the system boots, but plugging it in after Windows loads, I have no keyboard or mouse.

PC #2 works fine for a few minutes, then suddenly keyboard & mouse will stop working. Once I restart the PC it works again for a while.

Attempting to switch PC’s via the KVM either to or from PC 2 causes the primary (non KVM’d) display to flicker wildly for a good 15 seconds. It’s as if the DP is re-handshaking on the non-KVM monitor. There are possibly a couple resolution changes happening very quickly because I see all my desktop icons scatter and application windows rearrange. FWIW this never happened on the HDMI KVM I used previously (obviously HDMI and DP are a different protocol so that may not be worth much). It’s not a showstopper, but it makes the PC unavailable for the first ~15 secs after you switch to it, which is a non-negligible workflow disruption.

Keyboard is a Razer Huntsman and mouse is the Razer DeathAdder Pro 3 (connected via cable instead of wireless), but I have tried swapping them both with alternates and the problem remains.

I spent all night tonight troubleshooting and have come up with nothing. Had to go back to my old HDMI KVM for the time being.

Curious if anyone else has encountered any issues like this and how you overcame them.

Thanks in advance!

Never heard of a KVm stopping post.

For that keyboard and mouse try the usb3 ports not the USB hid ports.

Can you take a picture of how you have it cabled?

15 second switching time suggests a calling issue. There is no repeater in the KVm so each cable can work individually but instead think about it from the perspective of the GPU. Kvom in the mix? GPU sees cable+KVm+cable as one long signal corridor.

The USB cables between KVm and PC are for sure usb3 cables and not ie cables that came with phones which are usually sketchy?

If you can use a couple of 3 foot club3d cables as a starting point that would be good to test. Usually 3+6 type cable configs is fine but 3+3 is better :slight_smile:

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Thanks for the reply. I ordered some new USB 3 cables just to rule mine out, I used the ones that worked with my previous KVM.

The post issue is a weird one. Don’t even get the asus logo, but the monitor turns on and displays all black (at least not springing for OLED is good for something, right?). I need the system up this week but over the weekend I’ll open it up and see if I can get an error code from it.

For the DP cables I’m using the ones I bought from Level1Techs.

Will report back once I’ve received and tested the new usb cables. Cheers.

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What’s the display? Our cables aren’t as good as club3d but they’ll usually do the trick.

Are you using 120+200cm or 120+120? 200+200 may be too much for your setup if that’s what you’re using

The display is the Dell P2415Q. 24" 4K DP 1.2. For the cables I’m using 120+120.

The post code for the PC that won’t post when connected to the KVM is “keyboard controller error.”

Is this resolved??

I have made some progress! Will spend some time on it tonight and update the post. Thanks for following up.

All the dealbreaking issues are resolved!

Mouse and keyboard now work reliably after replacing my cables with USB 2.0 cables, which is all I really need for mouse and keyboard anyway.

PC that wouldn’t POST when the KVM was connected is now working fine after a CMOS clear. I had to redo my overclock but not a big deal in the grand scheme of things.

The only problems that remain is an occasional dropped key when I’m typing quickly, and the non-KVM monitor flickering when I switch to/from the PC that hosts it. It’s as if Windows “loses” the KVM monitor or it was switched off, so everything has to redraw (I was under the impression the KVM is supposed to emulate the monitor to all connected systems).

If you have any tips to resolve that, I’d love to hear them.

Other than that, I commend you for both finding and working on this KVM. I think those of us who have been in the game for a while tend to think of KVM’s as relatively trivial devices since the old CRT/PS2 days had us using ones that were just contact switches and they worked great. But these days KVMs are incredibly difficult to get right and this one is SOLID. Cheers.

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@wendell thanks again for following up. Now that the KVM is “working” there’s one thing driving me NUTS with frustration.

I have two computers connected to the KVM, both running Windows 10. Computer 1 has one monitor, run through the KVM. Computer 2 has two monitors, one connected directly via DisplayPort, and then also shares the same monitor with Computer 1 through the KVM.

Often, I’ll need to pull some data up on the screen on the direct-attached monitor on Computer 2, then switch the KVM to Computer 1 and refer to the data on Computer 2’s direct attached monitor.

But when I switch the KVM to Computer 1, Computer 2’s direct attached monitor flickers and the windows rearrange. The data that I need is no longer in the foreground window and other windows are stacked on top of it arbitrarily.

Then when I switch the KVM back to Computer 2, the screen flickers again, my desired window returns to the foreground, but it takes 10-15 secs before the PC is usable and keyboard input is accepted.

It’s like Computer 2 sees the KVM switchover as “unplugging” the monitor and Windows rearranges everything.

Any known workarounds for this?

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Windows 11 has “remember window positions” as a checkbox built in.

for windows 10 there is the “persistent windows” utility.

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Thank you! It still flickers but I can deal with that. This helped tremendously. Cheers!

After working with it for a week the problem of Windows rearranging foreground windows persists, even with the Persistent Windows utility.

That utility does a great job of restoring the windows to the preserved z-order after I’ve switched back to the computer via the KVM, but it does not affect window placement when I switch away.

On computer #2, I need to keep Excel in the foreground on the non-KVM monitor while I switch control over to Computer #1 and enter some values from the spreadsheet into computer #2 on the shared monitor.

When I switch control to computer #1, the non-KVM monitor’s windows rearrange and Excel is placed into an arbitrary z-order. It correctly comes back to the top once I switch back to computer #2.

I realize this is an issue with Windows and not with the KVM, but I’m curious if anyone knows any other remedies to this problem.

When I have time I may dive into the source for Persistent Windows and see if there’s anything that can be done.

There is a registry key.thwt defines the desktop size when no monitors are attached. By default it’s 1024x768 but you can make it an arbitrary size. Set it to the combined res of your desktop setup and the windows shouldn’t change z ordering

Will dig up a link if googling doesn’t reveal the fix

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This seems to have done it!

The details were rather difficult to find, and I ended up improvising a few of my own based on prior experience. Here’s what I did:

  • Browse to the key: HKLM\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration
  • Go through each folder of keys that begins with SIMULATED, expand the 00 nested within it.
  • Change PrimSurfSize.cx to the X resolution (make sure you choose DECIMAL when typing it in)
  • Change PrimSurfSize.cy to the Y resolution (again with DECIMAL)
  • Change Stride to the X resolution * 4 (for example, 7860 x resolution becomes 30720 for the Stride value, again in DECIMAL)
  • Expand the additional 00 child
  • Change ActiveSize.cx to X resolution (DECIMAL)
  • Change ActiveSize.cy to Y resolution (DECIMAL)
  • Repeat for all folders starting with SIMULATED under the CONFIGURATION tree
  • Restart Windows

OP if you want this opened again let me know, your issues seem to be solved tho