Seeking Solution for Inconsistent Visibility and Hot-Plug Detection with CP2105 Dual Port Passthrough

Incus
1

Scenario 1: Passthrough using unix-hotplug with Vendor/Product IDs

I configured passthrough as follows:

devices:
  cp2105:
    gid: "18"
    mode: "0660"
    productid: ea70
    type: unix-hotplug
    vendorid: 10c4

After the host computer boots, I can see both ttyUSB0 (Enhanced Com Port) and ttyUSB1 (Standard Com Port) under /dev on the host. However, when I check the Incus container, I only see ttyUSB1 (Standard Com Port). (Visibility is inconsistent; sometimes the container shows the Standard Com Port, and sometimes it shows the Enhanced Com Port.) Both ports become visible if I physically unplug and then plug the device back in.

Scenario 2: Passthrough using unix-char with udev Symlinks

"I also tried configuring the passthrough using the following configuration, relying on host-side udev rules to create consistent symlinks:

devices:
  cp2105_enh:
    gid: "18"
    mode: "0660"
    path: /dev/cp210x_enh
    required: "false"
    source: /dev/incus_serial_cp2105_enh
    type: unix-char
  cp2105_std:
    gid: "18"
    mode: "0660"
    path: /dev/cp210x_std
    required: "false"
    source: /dev/incus_serial_cp2105_std
    type: unix-char

My udev rule file is set up as follows:

#--- CP2105 (Enhanced Port) ---
SUBSYSTEMS=="usb", \
DRIVERS=="cp210x", \
ATTRS{interface}=="Enhanced Com Port", \
SYMLINK+="incus_serial_cp2105_enh", \
MODE="0660", GROUP="dialout"

#--- CP2105 (Standard Port) ---
SUBSYSTEMS=="usb", \
DRIVERS=="cp210x", \
ATTRS{interface}=="Standard Com Port", \
SYMLINK+="incus_serial_cp2105_std", \
MODE="0660", GROUP="dialout"

With this setup, after the host boots, I can see both cp210x_std and cp210x_enh under /dev in the Incus container. However, if I unplug and plug the device back in, only cp210x_enh remains visible. (Again, this is sometimes inconsistent; sometimes only cp210x_enh appears, and other times only cp210x_std appears.) Both ports become visible again if I restart the Incus container.

Question

“Given this situation, is there a method that allows both ports to be successfully passed through immediately after the host computer boots and ensures that hot-plug detection works reliably? Please note: The port I actually use is the Standard Com Port.”