I’ve been having a persistent issue with ‘sticking keys’ on my level1techs 4-Port KM switch. The issue is that when switching to my thinkpad t490s laptop, after a handful of keystrokes, one will decide to get stuck in the keypress-down state and any other input is completely broken until I switch the KM to my desktop then back to the thinkpad, where it will happen again soon after I begin typing (10s or so).
Both mouse (g502) and keyboard (keychron q6) are plugged into HID ports. I had hoped purchasing a QMK keyboard would have alleviated my woes w/ the Ducky and GMMK keyboards, but that hasn’t been the case. I did try a handful of different USB cables between the switch and laptop as well. Switching the keyboard to one of the USB3 ports does suppress the issue, but also ruins the actual convenience of having the KM switch.
If anyone knows a solution or answer to this, I’d be far too grateful.
What happens if you move the mouse to a USB3 port?
I will give this a test, ty - things may work well for a full day or two before they go haywire nonstop, so I’ll respond again when I have a ruling on this one way or the other.
Sadly after a few days of testing it did not seem to help. I installed Logitech’s software on the target laptop as well but I haven’t had any luck, the issue has persisted when the mouse is on a USB3.0 port.
@wendell - QMK boards shouuuld be fine right? The only issue I’ve seen are people who need to disable nkey rollover, but this seems like a different issue. Could the Logitech doggle be causing any issues? The mouse is logitech, but the keyboard is having issues…
@Jordlonk is the keyboard Bluetooth? If so can you try disabling that and then connecting the keyboard via the USB cable
Both mouse/keyboard are wired into the KM switch. My previous keyboards I disabled nkey rollover in hopes it might fix it, no luck there though, thus the QMK purchase.
It is worth noting that the issue seems to only happens on the t490s (it may have happened once or twice on my desktop, but it had to be a whiiiile back now). BIOS options for the laptop seem rather limited so I haven’t had luck with USB settings. Switch is plugged directly into USB ports.
Ooh… hmm let’s see what Wendell thinks
qmk should be fine. what ports on the t490s? do you have any other usb ports can you try? as dumb as it sounds… can you try via a usb hub?
some qmk keyboards that use an atmel bit-banged usb stack… won’t work. But STM32 etc with a real usb stack for qmk work (disable nkey, or use the nkey directive so that kvm leading keys come from the same virtual hid endpoint as the command key, and then nkey rollover is just fine)
nothing in the kvm has this type of incompatibility, for sure, so, something weird going on
Thanks for the suggestions. All of the USB type B ports on the thinkpad have been tried and found wanting. I was using an Anker USB C charging/hub hybrid initially and it was having issues there so I moved it over to a direct connection. I will find a more basic USB hub and give that a go instead and will report back.
Sadly it seems the issues have already popped up a few times. Mouse is still plugged into USB 3, and the KM Switch → laptop had a basic usb3.0 hub in between it.
As a bonus feature the KM switch decided that it didn’t want to switch PCs after receiving ctrl+ctrl+NUM commands this morning, leaving me stranded playing risk of rain rather than contributing to my work meeting. There are worse fates for a Friday. It would beep and physical presses of the buttons would briefly light up that PC’s light, then return to the previous PC immediately.
that really sounds like a keyboard that’s not quite hid OR some other non-hid device on a hid port causing hid crashes/weirdness. the usb stack is really implemented two different ways to harden against this type of thing – the usb3 side is totally isolated. if the only thing you’ve got on the hid side is the keyboard at this point… somethings strange with that keyboard/not hid enough
Thanks for the explanation. I’ve been doing a lot of troubleshooting on my side to try and sort things out but it has been nothing but a headache.
The issue only happens on the work laptop, with the desktop entirely unaffected it seems. Is there any reason/configuration of those USB ports that could potentially lead to this issue? Or is this 99.99% the keyboard?
If so, do you know of a cheap’ish keyboard that is known to work that I could try with and see if that truly is the cause?
a $5 dell or hp oem keyboard is useful for troubleshooting.
Is there a bios or dock update for the other machine (if a dock is in the mix)?
if you wanna try swapping KM switches we can but it might be easy to move the problem PC to another input on the KM to rule that out.
Thanks, just didn’t want to start buying random keyboards without knowing if they’d also be problematic. $5 isn’t unreasonable.
I have swapped the ports that the functional and problematic computers were using without success, so it wasn’t that, at least. I have tried a few ports on the switch in total, with only anecdotal evidence to show for the frequency of the issue.
…I will also look into a bios update, I probably should have thought about that sooner. No dock in the mix.