Fix LED-animations briefly pausing at bootup (ESP32 only) (#5337)

* fix bootup output glitch by using NVM stored credentials
* add ifdef guards for ESP8266

Author: DedeHai

wled00/wled.cpp

@@ -507,7 +507,7 @@ void WLED::setup()
   #ifndef ESP8266
   WiFi.setScanMethod(WIFI_ALL_CHANNEL_SCAN);
   #endif
-  WiFi.persistent(false);
+  WiFi.persistent(false); // note: on ESP32 this is only applied if WiFi.mode() is called and only if mode changes, use low level esp_wifi_set_storage() to change storage method immediately
   WiFi.onEvent(WiFiEvent);
   WiFi.mode(WIFI_STA); // enable scanning
   findWiFi(true);      // start scanning for available WiFi-s
@@ -670,6 +670,27 @@ void WLED::initAP(bool resetAP)
 
 void WLED::initConnection()
 {
+  #ifdef ARDUINO_ARCH_ESP32
+  static bool firstCall = true;
+  bool updateWiFiNVM = false;
+  if (firstCall) {
+    // check cached WiFi config in flash, esp_wifi_get_config still contains NVM values at this point
+    // note: connecting to the NVM stored wifi is much faster and prevents boot-up glitches on LEDs (there is no benefit on ESP8266)
+    wifi_config_t cachedConfig;
+    esp_err_t configResult = esp_wifi_get_config( (wifi_interface_t)ESP_IF_WIFI_STA, &cachedConfig );
+    if( configResult == ESP_OK ) {
+      if (strncmp((const char*)cachedConfig.sta.ssid, multiWiFi[0].clientSSID, 32) != 0 ||
+      strncmp((const char*)cachedConfig.sta.password, multiWiFi[0].clientPass, 64) != 0) {
+        updateWiFiNVM = true; // SSID or pass changed, update NVM at next WiFi.begin() call
+        DEBUG_PRINTLN(F("WiFi config NVM update triggered"));
+      }
+    }
+    firstCall = false;
+  }
+  else
+    esp_wifi_set_storage(WIFI_STORAGE_RAM); // do not update NVM credentials while running to prevent wear on flash
+  #endif
+
   DEBUG_PRINTF_P(PSTR("initConnection() called @ %lus.\n"), millis()/1000);
   #ifdef WLED_ENABLE_WEBSOCKETS
   ws.onEvent(wsEvent);
@@ -720,6 +741,11 @@ void WLED::initConnection()
     char hostname[25];
     prepareHostname(hostname);
 
+    #ifdef ARDUINO_ARCH_ESP32
+    if(updateWiFiNVM && selectedWiFi == 0)      // NVM only can store one wifi: store credentials of first WiFi even if multiple are configured
+      esp_wifi_set_storage(WIFI_STORAGE_FLASH); // temporary override WiFi.persistent(false) to store credentials in flash (is reset to RAM on next initConnection() call)
+    #endif
+
 #ifdef WLED_ENABLE_WPA_ENTERPRISE
     if (multiWiFi[selectedWiFi].encryptionType == WIFI_ENCRYPTION_TYPE_PSK) {
       DEBUG_PRINTLN(F("Using PSK"));