KVM switchbox locks keyboard and mouse

[Paul Martz]

I'm new to VMWare Workstation. Love it so far. Installation on Win11 and adding a Debian 13 Trixie guest has gone smoothly. Things are working fine. Except:

I share my monitor, keyboard, and mouse with two other machines via a KVM switchbox. If I switch away from the Windows 11 system, then return, the keyboard and mouse are inoperative. I get this behavior regardless of whether I leave keyboard focus with the host or the guest before I switch away.

I'm presently working around the issue with a spare keyboard and mouse, but this is less than ideal.

Are there any config options for my VM that might address this issue? Thanks in advance for any help.

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[Morc001]

  Hi Paul,

  Does the keyboard/mouse stop working in the Windows 11 host as well, or just the guest? Are the actual keyboard and mouse USB or PS/2? If the latter, and it stops working in the host as well, that is to be expected. PS/2 is not plug-and-play/hot-pluggable, I'm not sure how could you make the host see them again without a reboot. If USB, the guest keyboard/mouse is PS/2 by default, the keyboard for sure. By switching and removing the physical keyboard and mouse from the host could cause the guest to lose them too. I read somewhere that by editing the VMX file you can force the mouse to be USB, but I don't have a reference to any documentation.

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[Paul Martz]

Thanks for the reply. The physical keyboard and mouse are both USB, not PS2. The connection from the switchbox to the machine is also USB. And, yes, when I return to the machine running the VM, the keyboard and mouse are inoperative for both the host and the guest. The guest is still running; I can ssh into it. But neither the host nor guest respond to the keyboard and mouse. This behavior happens regardless of whether I leave focus in the host or the guest before I switch away.

Is it correct for me to assume this is supposed to work? I mean, this isn't a known problem, right? If that's the case, then maybe the issue is with my switchbox. It's rather old, and I don't believe it emulates a keyboard/mouse when switched away.

I'll do a bit of digging about vmx settings for a PS2 mouse. This might lead to a solution. Thanks.

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[Morc001]

Does this problem also happen when no VM is running. If so, I'd say this has nothing to do with VMWare, but even then I have a hard time imagining VMWare having to do anything with this, and would rather blame the switch or the keyboard or mouse. Although VMWare Workstation installed an "Enhanced keyboard driver" in past version, but that was discontinued in version 17 I think, and the newer version uninstalled it. USB devices should have no problem working. I'd try to also unplug and plug back the devices, and the switch to see if functionality restores after one or the other, although not sure what those would tell about where the problem lies :)

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[Paul Martz]

Sorry to resurrect this old thread. I thought I had the issue licked by modifying the VMX file to treat the keyboard and mouse as PS2 devices. But I was only dodging the issue. The real problem was the VMWare GUI, and I was avoiding it by using vmrun.exe at the command line.

As it turns out, the problem would rear its **** head any time I launched the VMWare Workstation GUI, then switched away from Windows. When I switched back, the keyboard and mouse were non-functional.

To finally resolve this problem, I launched services.msc and disabled the VMWare USB Arbitration service, thus preventing VMWare from grabbing any USB devices. This works because my guest doesn't need to access any host USB devices-the guest is console linux that I interface with using ssh from a remote machine. So, this works for me, but might not be a solution for others.

I'm surprised this issue isn't more commonplace. Makes me think the issue is specific to my particular make and model of switch box. It is rather antiquated. Maybe it's finally time to upgrade.

Thanks to everyone for the assistance.
-Paul

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[RaSystemlord]

For discussion, since you wondered "why this isn't more common place".

Putting switch usage aside, I never connect USB devices to any VM computer. There are reasons, like:

- I want to control on the Host what happens on each and every VM. Thus everything will go from Host to VMs, not directly from some random USB source
- you can easily copy files from Host to VM and vice versa. Normally, I use just drag&drop, or to be more careful copy&paste. For some things, I use "copy to network drive" directly, like for backups of some VM content. If none of those work, as they 1% of the time don't work directly, I use VMware provided filesharing at the Host.

And finally, connecting USB to a VM computer is just asking for trouble - at least when you have typically 3-5 different VMs open during a day and you DO have activity on the Host as well.

[goldeneye_007]

If I recall what you are describing by switching away from the GUI and losing keyboard and mouse sounds a lot like how actual PS2 keyboards and mice would behave. Once physically unplugged they would not re-establish a connection unless the machine was rebooted. That was a limitation in the PS2 protocol I believe. I personally have not run into the issue with VMware BUT all of our KVM's are PS2 based. For systems without PS2 ports we use PS2 to USB adapters. Yup those are some old KVM's, but if it ain't broke... One cool thing about these old KVM's is you can send a 'Reset Keyboard Mouse' command. I rarely have to use it but it is a great feature when you need it. It somehow corrects the PS2 issues that allow it to reconnect if it gets unplugged without rebooting the machine. It is possible you can work around the issue but any solution I can think of is overly complex and probably not worth the effort. In a nutshell you need to tell the machine to reset its PS2 protocol.

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