[SOLVED] Keyboard strokes missing when typing fast / USB vs PS/2?

satchmosgroove · 2020-01-06 18:53:48

I have the same keyboard at home and at work: a WASD Code v2. The one at home connected via PS/2 and through USB/Dock at work. The one at work often misses to register an "h" if I type fast. Of course, I have an h in my password, so this happens every time I unlock my screen. Keyboard itself seems fine, the switch seems fine. Is this maybe a USB vs PS/2 issue or even more delayed because it's slaved through a usb-c dock? It's always the h, it's on position 5 of 14 in my password. I use the same password at home, but never have an issue there. I doubt I type at different speed at home as the keyboard and OS/Kernel/Software versions are the same. Any ideas?

Last edited by satchmosgroove (2020-01-09 20:55:22)

seth · 2020-01-06 20:08:05

Is it always the "h" or always the "h" in certain tokens (eg. "bhj" or so - start from your password and try entirely different combos with long physical distances compared to the adjacent keys in your password)?
Can you switch the keyboards (and see whether it's indeed the bus or rather indeed the key)?
Is "H" affected as well?

"h" is suspicously centric on a qwerty/z keyboard so this smells like a long signal path being augmented by the next key, but I don't see how the bus would be the problem then…

Ropid · 2020-01-06 21:12:12

I remembered that there's a problem called "ghosting" with keyboards. Using that "ghosting" word while looking around, I then found this interesting page here:

https://www.mikemartin.co/system_guides … d_ghosting

According to that, there's a difference between USB and PS/2 that can make the problem show up more. Maybe that's what's happening for you and is the explanation for what you see at work vs. at home.

seth · 2020-01-06 21:35:29

It would actually rather be jamming (a method to deal with ghosting which creates artificial input)
To trigger this, you typically have to hit several keys in the same matrix block of the keyboard in rapid succession - and it's an extremely rare problem these days (and not related to the bus) - and mechanical keyboards aren't prone to this at all.

USB is limited reg. the key rollover, which refers to the ability to press several (non-modifier) keys at the same time and unlimited *parallel* key events are a marketing feature of "gaming keyboards".
This is sometimes confused with ghosting, but it isn't.
You must be typing *really* fast to trigger this on *sequential* input and even then it would be "some key in a sequence", not "h" in particular and all the time (at least not regardless of the context)

A single laggy key sounds more like a hardware issue with that particular key (or its wiring), thus the questions for the con-text ;-)

satchmosgroove · 2020-01-07 15:45:31

Of course, I forgot my other keyboard at home. It seems like once logged in, I don't have this issue typing along, only when unlocking. That's why I was tinking more along usb-dock-wakup-delay-kind-of-thing. But I will report back with both keyboards tested. Thanks already for all your input!

satchmosgroove · 2020-01-09 20:57:44

I am marking this solved. My other keyboard did better, so, looks like it's rather the switch, than anything else. Wasn't able to reproduce constantly, though. Will order some replacement parts and then we'll see. Thanks for all the pointers.

satchmosgroove · 2020-01-27 17:01:29

So, found out the real reason: I have a thinkpad usb-c dock and a x280 connected via usb-c. When the keyboard is in the USB2 spot with the keyboard icon I have missing keystrokes (notably the shift and h-key) if I type too fast. Once the keyboard is plugged into the USB-3 port, it works like a charm through the dock. go figure.

Arch Linux

#1 2020-01-06 18:53:48

[SOLVED] Keyboard strokes missing when typing fast / USB vs PS/2?

#2 2020-01-06 20:08:05

Re: [SOLVED] Keyboard strokes missing when typing fast / USB vs PS/2?

#3 2020-01-06 21:12:12

Re: [SOLVED] Keyboard strokes missing when typing fast / USB vs PS/2?

#4 2020-01-06 21:35:29

Re: [SOLVED] Keyboard strokes missing when typing fast / USB vs PS/2?

#5 2020-01-07 15:45:31

Re: [SOLVED] Keyboard strokes missing when typing fast / USB vs PS/2?

#6 2020-01-09 20:57:44

Re: [SOLVED] Keyboard strokes missing when typing fast / USB vs PS/2?

#7 2020-01-27 17:01:29

Re: [SOLVED] Keyboard strokes missing when typing fast / USB vs PS/2?

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