USBC Bricks Audio

KVM Model:

USBC v3


Problem:

When I am plugged into my kvm PulseAudio keeps dying over and over again (I have tried with pipewire as well and get the same behavior). I believe I found it is linked to problems with the kernel communicating with the sound card on the kvm? Here are a couple logging commands and their outputs below.

$ journalctl -e
 Jan 21 11:18:21 worktop kernel: usb 1-4.1.1: 1:1: cannot set freq 48000 to ep 0x1
Jan 21 11:18:26 worktop kernel: usb 1-4.1.1: 1:1: cannot set freq 48000 to ep 0x1
Jan 21 11:18:31 worktop kernel: usb 1-4.1.1: 1:1: cannot set freq 48000 to ep 0x1
Jan 21 11:18:36 worktop kernel: usb 1-4.1.1: 1:1: cannot set freq 48000 to ep 0x1
Jan 21 11:18:41 worktop kernel: usb 1-4.1.1: 1:1: cannot set freq 48000 to ep 0x1

and I believe the usb 1-4.1.1 refers to the sound card of the kvm

$ lsusb -t 
/:  Bus 001.Port 001: Dev 001, Class=root_hub, Driver=xhci_hcd/12p, 480M
    |__ Port 004: Dev 016, If 0, Class=Hub, Driver=hub/4p, 480M
        |__ Port 001: Dev 017, If 0, Class=Hub, Driver=hub/7p, 12M
            |__ Port 001: Dev 019, If 0, Class=Audio, Driver=snd-usb-audio, 12M
            |__ Port 001: Dev 019, If 1, Class=Audio, Driver=snd-usb-audio, 12M
            |__ Port 001: Dev 019, If 2, Class=Audio, Driver=snd-usb-audio, 12M

This currently renders my KVM unusable :\

I haven’t seen audio brick a KVM… @wendell?

The kvm isn’t bricked (probably bad word looking back), but the audio doesn’t work when plugged into kvm.

Do you have a powered usb hub to try?

In addition to the kvm? I usually just use a single computer dock and that works just fine

Right I was meaning in the blue USB 3.0 ports some people have had luck plugging a powered USB hub into it and running their problem child usb device through it

Surprisingly enough the above error doesn’t have anything to do with another usb device connected to the KVM, this problem comes from the KVM itself. The usb 1-4.1.1 I believe is actually just the internal sound card of the KVM.

Any further thoughts on this? strange thing is it was working for a couple weeks before this behavior too. If not, could I maybe exchange it for one of the HDMI models?

I have no idea. Contact “wendell at level1techs dot com” for more service options.

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Re-set up the kvm and am no longer having the issue! Maybe fixed by kernel updates or something. I did also switch to pipewire which may have helped (if anyone in the future has similar problems)

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Great to hear!

Had this problem occur on the second KVM I bought as well and found that unplugging and replugging in my webcam might have fixed things. Not sure if I didn’t do that the first time, but that seems to help if anyone else has a similar problem.