Random guest freeze

[stratoss]

Hello,

I have a homelab ProxMox 6.2-10 server running Debian 10 as a guest with PCI-e passthrough for the GPU & Audio card, as well as 4-port USB hub connected via 3m cable to the server, with usb passthrough for the 4 ports.

Once or twice per hour, on a random basis, the hub is being power cycled (as if it were dis-connected & re-connected), and at least once a day the guest freezes. On the dashboard it shows 99.9% memory usage & qemu-guest agent not running, the USB devices aren't being passed-through (the keyboard strokes are visualized on the server terminal instead in the guest) whilst the GPU-passthrough still works (I can see the xfce4 session on the monitors).

I have tried with a couple of hubs, different brands, absolutely the same behavior. Today I have tried to connect the keyboard & mouse directly through 3m USB cables and the issue is gone.

Does proxmox support USB hubs? Even if there is only 1 device connected to the hub, the issue re-appears.

Sample log from the host at the time of the event:

Aug 20 00:33:44 mainframe kernel: [834930.593979] usb 3-6.3: USB disconnect, device number 102
Aug 20 00:33:45 mainframe kernel: [834932.008303] usb 3-6.3: new low-speed USB device number 103 using xhci_hcd
Aug 20 00:33:45 mainframe kernel: [834932.162052] usb 3-6.3: New USB device found, idVendor=1c4f, idProduct=0002, bcdDevice= 1.10
Aug 20 00:33:45 mainframe kernel: [834932.163103] usb 3-6.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Aug 20 00:33:45 mainframe kernel: [834932.164086] usb 3-6.3: Product: USB Keyboard
Aug 20 00:33:45 mainframe kernel: [834932.165097] usb 3-6.3: Manufacturer: SIGMACHIP

Until yesterday I was using ProxMox 6.1, but because of those issues upgraded to 6.2 without any positive outcome.

Thank you in advance for the help!

 

[Stefan_R]

PVE uses a regular Debian under the hood, so anything supported by that should work just fine. That of course includes USB hubs.

USB is a somewhat fragile protocol though, and it would not surprise me if common hubs (even different vendors often use the same chips internally) simply don't have enough signal integrity to be safe to use over a 3m cable. Maybe also try a higher quality cable.

The guest freezes *might* be related to this, but don't have to. Check the logs (dmesg and journalctl) for the times when the freeze happens. Also check any logs in the guest from that time (after rebooting).

 

[stratoss]

Initially I had a 5 meter cable, then purchased a 3 meter high-quality one because of my though around the signal strength as well.

I'm using the very same 2 cables at the moment w/o hub and the keyboard/mouse are running smoothly w/o disconnect events in the syslog.

dmesg/journalctl doesn't come with anything different than the usb disconnect/re-connect similar to the syslog ones mentioned in my first post.