I picked up a L1 KVM (triple monitor, 5Gbps, 2 PC option) about 5 months ago and since the start it’s given me a small issue.
Every now and then, my PC will lose USB connection to my keyboard and mouse. I’m not unfamiliar with such problems, I work as an IT admin as part of my day job. That’s actually the reason I picked up the KVM. I started a new job working from home and I wanted to use the same displays, KB, and mouse for both my work and home PC use. Work furnished me with a Lenovo laptop with a thunderbolt dock, the dock has 2x display port and one HDMI. I used a recommended HDMI to displayport adapter and I was off to the races. I’ll be clear here: the Lenovo has zero issues. It works flawlessly apart from some small display issues when I switch the KVM over to it, usually requiring a power cycle of a display. I expect that’s more of a display problem than anything.
The issue is with my personal rig. I have a Dell precision 7910 rack as my own computer (it’s crazy to use it as a desktop, but I have my reasons). The problem is that it doesn’t have USB 3.0 available on the back, so I added a USB 3.0 controller for the purpose, but the precision doesn’t really have the usual power headers inside the case, so I found one that works off of PCIe bus power only, and so far (prior to the KVM issues) it’s given me no issues. Enter the KVM. Now, every so often, usually when I’m playing games, I’ll get notification tones from Windows (W10 pro) that a device has disconnected. A second later it will reconnect with the appropriate tones played as well. During that 1-2s of downtime, the keyboard and mouse are quite simply dead. Unable to be used. This poses a problem when gaming, as you might imagine
For completeness, my keyboard is a fairly standard mechanical from CM Storm. My mouse is a Logitech G703, and I’m using the power play matt thing to keep it charged. Also on USB from the KVM is a displayport dual adapter (to add two more displays, yes, I have five in total). I suspect the powerplay mat is pulling too much current for my poor USB card, and it resets the port, but the displays don’t seem to have any issues, though further testing is required here.
I managed to check my power draw on my personal system’s usb line, and found that an attached USB drive was pulling more power than the line to the KVM. I pulled the drive thinking that may reduce the power load and fix the problem, but it didn’t.
For those not familiar, the power play matt from Logitech functions both to wirelessly charge the mouse, and also acts as the wireless reciever for the mouse, so simply plugging it in elsewhere isn’t an option. I tried plugging it into the hid ports on the KVM, and the USB 3 ports on it and neither seems to make any difference. The only other thing on the KVMs USB is a verifi fingerprint scanner, which was recently added, the problem existed before it was added.
Nothing is appearing in the windows logs when it happens. Not even device plug/unplug messages IIRC. No errors from the USB controller driver… Nothing. I’m at a loss.
I’m hoping someone from the L1 forums here can help me brainstorm new ideas to try on order to fix the problem, and what may be the cause. My only idea right now is to butcher a USB cable to inject 5v power to the mouse to see if it fixes the issue (either between the mouse and KVM or between the KVM and PC). Given that my work system has no such problem, I’m more inclined to think it’s the USB card on the PC that’s the problem, so I would probably want to inject power between the PC and KVM.
The “plan” (if you can call it) is entirely based on the fact that the KVM is drawing more from the USB port than the port can deliver, but without issues from the USB attached displays, I’m not sure. It’s possible that the display link connected displays are not affected because they just keep showing whatever is in the framebuffer while the PC sorts itself out, which is why I need further testing on that front.
I would think that this is just too much for the KVM to handle, except, why would the Lenovo work fine if that was the case…
Any further ideas or suggestions are appreciated.