Add WLED_QEMU WiFi workaround to prevent crashes

QEMU doesn't emulate WiFi hardware. When WiFi functions like
WiFi.disconnect(), WiFi.mode(), WiFi.begin() try to access WiFi
registers (address range 0x60033xxx), firmware crashes with
LoadStorePIFAddrError.

Crash example:
- Arduino Event: 0 - WIFI_READY
- Guru Meditation Error: Core 0 panic'ed (LoadStorePIFAddrError)
- EXCVADDR: 0x60033c00

Solution:
- Extended WLED_QEMU flag to also skip WiFi initialization
- Wrapped all WiFi calls in initConnection() with #ifndef WLED_QEMU
- Disabled WiFi AP management code (esp_wifi_ap_get_sta_list, etc.)
- Protected WiFi.disconnect() call when switching to ethernet
- Network connectivity works via ethernet only (QEMU user-mode networking)

Documentation updates:
- docs/QEMU-ISSUES.md: Added WiFi hardware workaround section
- e2e-tests/README.md: Updated troubleshooting with WiFi info

This allows QEMU testing to proceed without WiFi-related crashes.
The WLED_QEMU flag should only be used for QEMU testing builds.

Co-authored-by: softhack007 <[email protected]>

Author: Copilot

docs/QEMU-ISSUES.md

@@ -28,14 +28,27 @@ The build uses ESP32-POE board configuration (index 2):
 
 This configuration is compatible with QEMU's `open_eth` model, which emulates standard ESP32 RMII ethernet interface.
 
-### QEMU Ethernet Hardware Workaround
-**Critical**: The build includes `WLED_QEMU` flag which skips actual ethernet hardware initialization (`ETH.begin()`). This is necessary because:
-- QEMU's `open_eth` model doesn't fully emulate all ethernet MAC hardware registers
-- Calling `ETH.begin()` crashes with `LoadStorePIFAddrError` in `emac_ll_clock_enable_rmii_output`
-- The crash occurs when trying to enable RMII clock output (hardware register access at 0x3ff6980c)
-- With `WLED_QEMU` defined, the code skips hardware init but marks ethernet as configured
-- Network stack still functions via QEMU's user-mode networking (slirp)
-- HTTP server and web UI work without actual hardware initialization
+### QEMU Hardware Workarounds
+
+The build includes `WLED_QEMU` flag which provides workarounds for hardware that QEMU doesn't emulate:
+
+#### Ethernet MAC Hardware
+- **Problem**: QEMU's `open_eth` model doesn't fully emulate ESP32 ethernet MAC hardware registers
+- **Symptom**: Firmware crashes with `LoadStorePIFAddrError` in `emac_ll_clock_enable_rmii_output` when `ETH.begin()` tries to access register at 0x3ff6980c
+- **Solution**: `WLED_QEMU` flag skips `ETH.begin()` hardware initialization
+- **Result**: Ethernet is marked as configured without hardware init; network stack still functions via QEMU's user-mode networking (slirp)
+
+#### WiFi Hardware
+- **Problem**: QEMU doesn't emulate WiFi hardware at all
+- **Symptom**: Firmware crashes with `LoadStorePIFAddrError` when WiFi functions (`WiFi.disconnect()`, `WiFi.mode()`, `WiFi.begin()`, etc.) try to access WiFi hardware registers (address range 0x60033xxx)
+- **Example crash**:
+  ```
+  Arduino Event: 0 - WIFI_READY
+  Guru Meditation Error: Core 0 panic'ed (LoadStorePIFAddrError)
+  EXCVADDR: 0x60033c00
+  ```
+- **Solution**: `WLED_QEMU` flag also skips all WiFi initialization in `initConnection()` and elsewhere
+- **Result**: WiFi functions are disabled; network connectivity works via ethernet only through QEMU's user-mode networking
 
 **For real hardware**: Remove the `WLED_QEMU` flag - it should only be used for QEMU testing.
 

e2e-tests/README.md

@@ -122,10 +122,12 @@ npx playwright show-report
 
 **Ethernet/network connection issues:**
 - QEMU provides DHCP server (10.0.2.0/24 network, guest IP 10.0.2.15)
-- The build uses `WLED_QEMU` flag to skip ethernet hardware initialization (prevents LoadStorePIFAddrError crash)
+- The build uses `WLED_QEMU` flag to skip hardware initialization (prevents crashes):
+  - Ethernet MAC hardware init (`ETH.begin()`) is skipped - causes LoadStorePIFAddrError crash
+  - WiFi initialization is completely disabled - WiFi hardware not emulated, causes LoadStorePIFAddrError
 - Network still works via QEMU's user-mode networking (slirp)
 - If DHCP fails, enable static IP in `platformio.ini` (see comments in file)
-- Check QEMU output for "ETH Connected" or "Ethernet configured for QEMU" message
+- Check QEMU output for "Ethernet configured for QEMU" and "WiFi disabled" messages
 - Port forwarding: ESP32 port 80 → localhost:8080
 
 **Tests fail with connection errors:**

wled00/wled.cpp

@@ -1118,6 +1118,9 @@ void WLED::initConnection()
   ws.onEvent(wsEvent);
   #endif
 
+#ifndef WLED_QEMU
+  // QEMU: Skip WiFi initialization - WiFi hardware not emulated
+  // The firmware crashes with LoadStorePIFAddrError when WiFi functions try to access hardware registers
   WiFi.disconnect(true);        // close old connections
 #ifdef ESP8266
   WiFi.setPhyMode(force802_3g ? WIFI_PHY_MODE_11G : WIFI_PHY_MODE_11N);
@@ -1173,6 +1176,12 @@ void WLED::initConnection()
 #else
   wifi_set_sleep_type((noWifiSleep) ? NONE_SLEEP_T : MODEM_SLEEP_T);
 #endif
+#else
+  // QEMU mode: Skip all WiFi initialization
+  DEBUG_PRINTLN(F("initConnection: QEMU mode - skipping WiFi initialization"));
+  USER_PRINTLN(F("initConnection: *** QEMU mode - WiFi disabled, using ethernet only ***"));
+  lastReconnectAttempt = millis();
+#endif
 }
 
 void WLED::initInterfaces()
@@ -1350,6 +1359,7 @@ void WLED::handleConnection()
   }
   #endif
 
+#ifndef WLED_QEMU
   byte stac = 0;
   if (apActive) {
 #ifdef ESP8266
@@ -1371,6 +1381,7 @@ void WLED::handleConnection()
       }
     }
   }
+#endif // WLED_QEMU
   if (forceReconnect) {
     USER_PRINTLN(F("Forcing reconnect."));
     initConnection();
@@ -1406,8 +1417,10 @@ void WLED::handleConnection()
     if (Network.isEthernet()) {
      #if ESP32
      USER_PRINTLN(" via Ethernet (disabling WiFi)");
+     #ifndef WLED_QEMU
      WiFi.disconnect(true);
      #endif
+     #endif
     } else {
      USER_PRINTLN(" via WiFi");
     }