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fred777
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Joined: 01/07/2021
Location: United Kingdom
Posts: 97

Posted: 03:40pm 19 Jul 2026

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Hi, again.

I tried to use hdmi/usb version of the Picomite with a KVM Switch. The keyboard does not work reliably and often drops some characters or suddenly repeats a key endlessly. The same keyboard is working fine when attached to the picomite directly and the KVM switch is fine under Windows&Linux. Also tried different keyboards, but no change.

Data:
Original Pi Pico2 V6.03.00 - but the error happened with older versions as well
KVM: ATEN CS1794 Cubiq

Is there anything that might explain or even fix this?

Cheers,
Fred

Martin H.

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Joined: 04/06/2022
Location: Germany
Posts: 1485

Posted: 05:16pm 19 Jul 2026

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Hi Fred,
With the KVM switch, it seems you don’t have a permanent connection between the Pico and the Keyboard.
I don’t think the devices are meant to be unplugged and plugged back in whilst in use. After all, that’s all the KVM switch does.
It’s an interesting problem, but unfortunately I’ve got no other solution than to use a separate keyboard with the Pico.

Cheers
Martin

'no comment

Amnesie
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Joined: 30/06/2020
Location: Germany
Posts: 763

Posted: 06:51pm 19 Jul 2026

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Hi

"... or suddenly repeats a key endlessly." same here. I also have to use it without a KVM switch.

Greetings
Daniel

fred777
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Joined: 01/07/2021
Location: United Kingdom
Posts: 97

Posted: 07:17pm 19 Jul 2026

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No, this is not a cheap kvm, the clients don’t know
if you’re switching, usb stays connected and monitor as well (edid emulation)

Footnote added 2026-07-20 16:59 by fred777
I was referring to “ it seems you don’t have a permanent connection between the Pico and the Keyboard.
I don’t think the devices are meant to be unplugged and plugged back in whilst in use. After all, that’s all the KVM switch does.” … just to avoid confusion

Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 8963

Posted: 07:49pm 19 Jul 2026

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Bear in mind that this isn't a "full fat" USB stack like you find in Windows. It's TinyUSB - appreciably cut down to be shoehorned into the available storage and, particularly, RAM. What you are seeing may not be a fault, merely something that was never included.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

fred777
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Joined: 01/07/2021
Location: United Kingdom
Posts: 97

Posted: 09:38pm 19 Jul 2026

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Understood, I’ll have a look on the TinyUsb GitHub
for similar issues

fred777
Regular Member

Joined: 01/07/2021
Location: United Kingdom
Posts: 97

Posted: 07:03am 20 Jul 2026

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Amnesie said Hi

"... or suddenly repeats a key endlessly." same here. I also have to use it without a KVM switch.

Greetings
Daniel

What make/type of kvm are you using?
I’m trying out different kvms to see if the problem can be reproduced

Amnesie
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Joined: 30/06/2020
Location: Germany
Posts: 763

Posted: 08:13am 20 Jul 2026

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Hi,
I am using the

AIMOS AM-KVM201-CL

Greetings
Daniel

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