[BUG] {RVC4 PoE devices (OAK-4-PRO-W) cannot connect via IP — driver loops indefinitely}

[AnishMathewOommen]

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Check if issue already exists
Searched "X_LINK_GATE RVC4 depthai-ros github luxonis" and "driver loops indefinitely PoE IP depthai-ros" — no existing issue found.

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Describe the bug
When connecting to an RVC4-based OAK PoE device (OAK-4-PRO-W) via IP, the driver loops indefinitely printing "Connecting to the device using ip: <device-ip>" without ever connecting, throwing an error, or publishing any topics.

The root cause is in depthai_ros_driver/src/driver.cpp in the startDevice() function. The IP connection block only allows connection when device state is X_LINK_UNBOOTED or X_LINK_BOOTLOADER. However, RVC4 devices report X_LINK_GATE as their ready state, which is not handled — so the connection is silently skipped every retry.

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Minimal Reproducible Example

1. Connect an OAK-4-PRO-W via PoE
2. Set driver.i_ip in params file to the camera's IP
3. Launch:

ros2 launch depthai_ros_driver_v3 driver.launch.py params_file:=<your_params>.yaml

4. Driver prints "Connecting to the device using ip: <device-ip>" in an infinite loop. No error, no topics.

Confirmed Python depthai v3 connects fine to the same device:

import depthai as dai
with dai.Device(dai.DeviceInfo('<device-ip>')) as d:
    print(d.getDeviceName())  # prints OAK-4-PRO-W
    print(d.getConnectedCameras())  # prints all 3 cameras

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Expected behavior
Driver should successfully connect to RVC4 PoE devices that report X_LINK_GATE state and start publishing topics.

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Screenshots
N/A

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Attach system log

• OS: Ubuntu 22.04 (inside Docker container)
• ROS version: ROS 2
• ROS distribution: Humble
• depthai-ros built from source (v3_humble branch)
• depthai/depthai-core installed from source as depthai_v3 package in workspace

Package versions:

depthai (Python):              3.1.0
depthai-core (C++ / depthai_v3): 3.2.2
depthai-ros-driver-v3:         3.1.1
depthai-ros-msgs-v3:           3.1.1
depthai-bridge-v3:             3.1.1
depthai-descriptions-v3:       3.1.1

Device state observed via Python:

X_LINK_GATE (XLinkDeviceState)
Platform: X_LINK_RVC4
Protocol: X_LINK_TCP_IP

Fix applied locally:
In depthai_ros_driver/src/driver.cpp, changed:

if(info.state == X_LINK_UNBOOTED || info.state == X_LINK_BOOTLOADER) {

to:

if(info.state == X_LINK_UNBOOTED || info.state == X_LINK_BOOTLOADER || info.state == X_LINK_GATE) {

After rebuilding, driver connects and publishes topics successfully.

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Additional context

• Device: OAK-4-PRO-W
• Connection: PoE over Ethernet
• Platform: RVC4
• X_LINK_GATE is the normal ready state for RVC4 PoE devices
• Linked PR: PR #779