LEDMatrix/docs/archive/WIFI_ETHERNET_AP_MODE_FIX.md

WiFi Monitor Ethernet Check Fix

Problem

The WiFi monitor service was enabling Access Point (AP) mode whenever WiFi was disconnected, even when the Raspberry Pi was connected via Ethernet. This caused:

• AP mode to activate unnecessarily when Ethernet was available
• Potential network conflicts
• Confusion for users with hardwired connections

Solution

Updated the WiFi manager to check for Ethernet connectivity before enabling AP mode. AP mode will now only be enabled when:

• WiFi is NOT connected AND
• Ethernet is NOT connected

Changes Made

1. Added Ethernet Detection Method

Added _is_ethernet_connected() method to src/wifi_manager.py that:

• Checks for active Ethernet interfaces (eth0, enp*, etc.)
• Verifies the interface has an IP address
• Uses nmcli if available, falls back to ip command
• Returns True if Ethernet is connected and has an IP

2. Updated AP Mode Enable Logic

Modified enable_ap_mode() to:

• Check for Ethernet connection before enabling AP mode
• Return an error message if Ethernet is connected: "Cannot enable AP mode while Ethernet is connected"

3. Updated AP Mode Management Logic

Modified check_and_manage_ap_mode() to:

• Check both WiFi and Ethernet status
• Only enable AP mode if both are disconnected
• Disable AP mode if either WiFi or Ethernet connects
• Log appropriate messages for each scenario

4. Enhanced Logging

Updated wifi_monitor_daemon.py to:

• Log Ethernet connection status
• Include Ethernet status in state change detection
• Log when AP mode is disabled due to Ethernet connection

Testing

Verify Ethernet Detection

# Check if Ethernet is detected
python3 -c "
from src.wifi_manager import WiFiManager
wm = WiFiManager()
print('Ethernet connected:', wm._is_ethernet_connected())
"

Test AP Mode Behavior

1. With Ethernet connected:

   # AP mode should NOT enable
   sudo systemctl restart ledmatrix-wifi-monitor
   sudo journalctl -u ledmatrix-wifi-monitor -f
   # Should see: "Cannot enable AP mode while Ethernet is connected"
   

2. With Ethernet disconnected and WiFi disconnected:

   # Disconnect Ethernet cable
   # AP mode SHOULD enable
   sudo journalctl -u ledmatrix-wifi-monitor -f
   # Should see: "Auto-enabled AP mode (no WiFi or Ethernet connection)"
   

3. With Ethernet connected and WiFi connects:

   # Connect WiFi
   # AP mode should disable if it was active
   sudo journalctl -u ledmatrix-wifi-monitor -f
   # Should see: "Auto-disabled AP mode (WiFi connected)"
   

4. With Ethernet connects while AP is active:

   # Connect Ethernet cable while AP mode is active
   # AP mode should disable
   sudo journalctl -u ledmatrix-wifi-monitor -f
   # Should see: "Auto-disabled AP mode (Ethernet connected)"
   

Deployment

On Existing Installations

1. Restart the WiFi monitor service:

   sudo systemctl restart ledmatrix-wifi-monitor
   

2. If AP mode is currently active and Ethernet is connected, it will automatically disable:

   # Check current status
   sudo systemctl status hostapd
   
   # The service should automatically disable AP mode within 30 seconds
   # Or manually disable:
   sudo systemctl stop hostapd dnsmasq
   

3. Verify the fix:

   # Check logs
   sudo journalctl -u ledmatrix-wifi-monitor -n 20
   
   # Should see messages about Ethernet connection status
   

On New Installations

The fix is included automatically - no additional steps needed.

Behavior Summary

WiFi Status	Ethernet Status	AP Mode	Reason
Connected	Connected	❌ Disabled	Both connections available
Connected	Disconnected	❌ Disabled	WiFi available
Disconnected	Connected	❌ Disabled	Ethernet available
Disconnected	Disconnected	✅ Enabled	No network connection

Troubleshooting

AP Mode Still Enables with Ethernet Connected

1. Check Ethernet detection:

   python3 -c "
   from src.wifi_manager import WiFiManager
   wm = WiFiManager()
   print('Ethernet connected:', wm._is_ethernet_connected())
   "
   

2. Check network interface status:

   nmcli device status
   # OR
   ip addr show
   

3. Verify Ethernet has IP address:

   ip addr show eth0
   # Should show an "inet" address (not just 127.0.0.1)
   

Ethernet Not Detected

If Ethernet is connected but not detected:

1. Check interface name:

   ip link show
   # Look for Ethernet interfaces (may be eth0, enp*, etc.)
   

2. Check NetworkManager status:

   sudo systemctl status NetworkManager
   

3. Manually check interface:

   nmcli device status | grep ethernet
   

Related Files

• src/wifi_manager.py - Main WiFi management logic
• scripts/utils/wifi_monitor_daemon.py - Background daemon that monitors WiFi/Ethernet
• scripts/install/install_wifi_monitor.sh - Installation script for WiFi monitor service

Notes

• The Ethernet check uses nmcli if available (preferred), otherwise falls back to ip command
• The check verifies that the interface has an actual IP address (not just link up)
• AP mode will automatically disable within 30 seconds (check interval) when Ethernet connects
• Manual AP mode enable via web interface will also respect Ethernet connection status