Re: [Hampshire] [OT] More IT than Linux: Bizarre KVM issue.

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Author: rmluglist2--- via Hampshire
Date:  
To: 'Hampshire LUG Discussion List'
CC: rmluglist2
Subject: Re: [Hampshire] [OT] More IT than Linux: Bizarre KVM issue.
Hi Dom

I'll dig the link out but, fwiw, I finally sorted this out - and it's not a KVM issue. It's actually to do with USB and particularly the way in which USB is "serviced" by Windows. As I said in the OP, I'd not come across these errors on Linux or Mac.

Suffice to say, if you're having the same problems I was (occasional mouse and or keyboard freeze, then keyboard repeating for no reason), the answer is delightfully low tech: change the USB port until you find one that works. My new work laptop (HP Elitebook) exhibited the same problems as my own Windows machines. My KVM was connected to the work laptop via a spare USB A port and was showing the errors above. I moved the KVM to a USB C port on the laptop (via a tiny A to C adaptor) and it's been solid every since - over 3 weeks now.

I did some reading into this - though I've lost the link now. It turns out Windows does not treat all USB ports equally (and it's not to do with USB 2 or 3 etc). A lot (apparently) depends on the order in which the ports are serviced by Windows. It _seems_ (YMMV) that USB C (being far more popular nowadays) is handled before USB A ports. This, of course, didn't explain the issue on my home PC (which doesn't have USB C) but changing the USB port on that has fixed that too.

As I say, YMMV, but changing the port does seem to be the workaround.

Thanks
Rob

-----Original Message-----
From: Hampshire <hampshire-bounces@???> On Behalf Of Dom Rodriguez/shymega via Hampshire
Sent: 22 May 2022 16:52
To: 'Peter Alefounder' <hampshire@???>
Cc: Dom Rodriguez/shymega <shymega@???>
Subject: Re: [Hampshire] [OT] More IT than Linux: Bizarre KVM issue.

Hi,

I have a cheap DP KVM switch, which is a bit unreliable. I don't have any DVI devices anymore! 😃

I do work on Input Leap, a fork of Barrier KVM switch software (itself a fork of Synergy 1.x), but I've moved my focus to my own hybrid h/w / s/w KVM switch, called Continuity. The only problem so far is that the idea was for video streaming, and for work laptops, it needs a driver. I haven't written the USB or video streaming drivers yet. No experience with Windows or macOS kernels...

Can you link to the 8-port KVM switch? I'm running out of ports on my 4-port KVM switch, and with the work laptop now, I need an extra port!

Onto your issue, the only thing I tend to experience is USB bus malfunctions. Generally, it recovers after I turn off the USB hub and on again after switching...

Thanks.

On Thu, May 5, 2022, at 11:40 AM, rmluglist2--- via Hampshire wrote:
> Hi all
>
> Has anyone had an issue with a KVM where there’s a distinct lag and
> then key repeat problem on some of the boxes and not others?
>
> I have a 4 port (Belkin USB / DVI) KVM switch. Two machines are
> Windows 10 (on which this problem is intermittent) and the other 2
> machines are a Mac and a Linux (Fedora) box. On the non-Windows
> machines, the issue doesn’t exist.
>
> I’ve tried connecting the kbd straight into the windows machines and
> that fixes the problem. Then when I revert to connecting via the kvm,
> the problem is intermittent i.e. happens about 5%-10% of the time. As
> such, while this would point toward a faulty KVM, why is this only
> occurring on Windows machines? I’ve checked Device manager and the
> same device is detected whether via the kvm or directly connected.
>
> As I say, I’m loathe to change the kvm because a) they’re expensive
> and I’d actually have to replace the 4 port with an 8-port which is £180:
> very pricy for me. And b) Linux and Mac have no problems. I could
> replace the 4 port with another 4 port but I have been looking to
> expand connections for ages.
>
> And c) I realise I could drop Windows altogether but one’s provided by
> my employer – so that has to be Windows
>
> Any thoughts anyone?
>
> Cheers
> rob
> --
> Please post to: Hampshire@??? Web Interface:
> https://mailman.lug.org.uk/mailman/listinfo/hampshire
> LUG URL: http://www.hantslug.org.uk
> --------------------------------------------------------------


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Kind regards,
--
Dom Rodriguez (also known as shymega)


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