[SOLVED] No /dev/serial nor /dev/ttyUSB* after plugging in USB devices?

S

starob

New Member
Jun 24, 2024
11
0
1
I have a PVE 8.3.5 installation on a Intel N100 based mini PC with 2 VM's and several LXC's. It runs fine since almost 1 year. One VM is a Home Assistant VM that I installed using a helper script from here: https://tteck.github.io/Proxmox/. A Sonoff Zigbee USB stick is assigned to the HA VM via USB passthrough and used by Zigbee2MQTT (Z2M). I recently added a second USB device (nanoCUL = Arduino Nano 3 with CC1101) to read data from my watermeter. Is is also attached to the VM via USB passthrough. Everything initially worked until I rebooted the HA VM.

Then the Z2M add-on did not start any more because it claims that /dev/ttyUSB0 is not available. In HAOS I can see the 2 USB devices in /dev (ttyUSB0 and ttyUSB1) and also in /dev/serial/by-id. The strange thing though is that there are no /dev/ttyUSB* devices and no /dev/serial directory visible in Proxmox. Another strange thing is that I need to unplug the nanoCUL and reboot the HA VM to make Z2M work again.

dmesg includes a lot of messages about USB devices being connected to ttyUSB* but then beeing disconnected immediately afterwards. That would explain why they don't appear in Proxmox. But they are still usable in my VM. I'm confused ....

Any help would be highly appreciated.

Here is more detailed info:

Code: 
root@pve:~# uname -a
Linux pve 6.8.8-1-pve #1 SMP PREEMPT_DYNAMIC PMX 6.8.8-1 (2024-06-10T11:42Z) x86_64 GNU/Linux

Code: 
root@pve:~# lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 009: ID 10c4:ea60 Silicon Labs CP210x UART Bridge
Bus 001 Device 016: ID 1a86:7523 QinHeng Electronics CH340 serial converter
Bus 001 Device 004: ID 8087:0026 Intel Corp. AX201 Bluetooth
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Code: 
root@pve:~# ls /dev/ttyUSB*
ls: cannot access '/dev/ttyUSB*': No such file or directory
root@pve:~# ls /dev/serial
ls: cannot access '/dev/serial': No such file or directory


VM config:

Code: 
## Home Assistant OS
#### https%3A//github.com/tteck/Proxmox
agent: 1
bios: ovmf
boot: order=scsi0
cores: 4
cpu: host
efidisk0: local-lvm:vm-106-disk-0,efitype=4m,size=4M
localtime: 1
memory: 6124
meta: creation-qemu=8.0.2,ctime=1692884225
name: homeassistant
net0: virtio=BC:24:11:66:3A:86,bridge=vmbr0
numa: 0
onboot: 1
ostype: l26
parent: HA-2025-3-4-Pre-Updates
scsi0: local-lvm:vm-106-disk-1,cache=writethrough,discard=on,size=32G,ssd=1
scsihw: virtio-scsi-pci
smbios1: uuid=e086e66f-c8ea-4174-9be5-258754273310
sockets: 1
startup: order=3,up=120
tablet: 0
tags: proxmox-helper-scripts
usb0: host=10c4:ea60
usb1: host=1a86:7523
usb2: host=1-1
vmgenid: 7de3a885-ed24-400a-8561-bc760903d612

Code: 
Welcome to the Home Assistant command line.

System information
  IPv4 addresses for enp0s18: 192.168.1.200/24
  IPv6 addresses for enp0s18: fe80::fb5c:adb:54fc:e53c/64

  OS Version:               Home Assistant OS 15.1
  Home Assistant Core:      2025.3.4

  Home Assistant URL:       http://homeassistant.local:8123
  Observer URL:             http://homeassistant.local:4357
~ $ lsusb
Bus 003 Device 001: ID 1d6b:0003 Linux 6.12.20-haos xhci-hcd xHCI Host Controller
Bus 002 Device 002: ID 10c4:ea60 ITead Sonoff Zigbee 3.0 USB Dongle Plus
Bus 001 Device 001: ID 1d6b:0001 Linux 6.12.20-haos uhci_hcd UHCI Host Controller
Bus 002 Device 003: ID 1a86:7523 USB Serial
Bus 002 Device 001: ID 1d6b:0002 Linux 6.12.20-haos xhci-hcd xHCI Host Controller
~ $ ls /dev/ttyUSB*
/dev/ttyUSB0  /dev/ttyUSB1
~ $ ls /dev/serial/by-id
usb-1a86_USB_Serial-if00-port0                                                           usb-ITead_Sonoff_Zigbee_3.0_USB_Dongle_Plus_f493f36eea5fec11bc7d2c5f25bfaa52-if00-port0
~ $ ls -l /dev/serial/by-id
total 0
lrwxrwxrwx    1 root     root            13 Apr  2 14:24 usb-1a86_USB_Serial-if00-port0 -> ../../ttyUSB1
lrwxrwxrwx    1 root     root            13 Apr  2 13:54 usb-ITead_Sonoff_Zigbee_3.0_USB_Dongle_Plus_f493f36eea5fec11bc7d2c5f25bfaa52-if00-port0 -> ../../ttyUSB0
~ $
 
This looks like normal behavior to me. I have a similar setup and I also have neither have /dev/serial nor /dev/ttyUSB for the device. This makes sense, because the device itself is passed thrugh the VM and thus cannot be used in the host.

Run
Code: 
usb-devices
in your host, this should list the devices.
 
I see. That makes sense. And yes, the host sees the devices. This is the strange thing that both the host and the VM (HAOS) sees the devices but still has a problem to access it after a reboot. Well, actually the add-on has a problem to access it. And add-ons are docker containers running on HAOS which in turn is a custom built Linux generated from buildroot. The other strange thing is that I can only make it work again if I remove the second USB device before restarting the VM. I've tried swapping USB ports and using PVE "USB Vendor/Device ID" instead of USB Port passthrough but that did not help.
 
I just figured out that with every reboot the usb device/USB port assignment in the VM changes. So when the zigbee stick is attached to ttyUSB0 it changes to ttyUSB1 after the reboot and then to ttyUSB0 again. That's why it work with the zigbee stick only because it always is ttyUSB0. Now need to find out how to fix this.
 
Impact said:
Use the path you get via ls -l /dev/serial/by-id/.
Click to expand...
Thank you. I tried this but although it should work it does not. The Z2M add-on logs an error:
Error: USB adapter discovery error (No valid USB adapter found). Specify valid 'adapter' and 'port' in your configuration.
Seems to be an issue with this add-on when using serial by-id device names.
 
For me it works like this:

Proxmox Passthrugh
1743664954650.png

Z2M config
Code: 
port: >-
  /dev/serial/by-id/usb-Silicon_Labs_Sonoff_Zigbee_3.0_USB_Dongle_Plus_0001-if00-port0
adapter: zstack
 
  • Like
Reactions: starob
You must log in or register to reply here.
Top Bottom