WiFi reconnect fails after disconnecting and turning off WiFi chip power on Raspberry Pi Pico W

[toreis-up]

Description

I'm encountering an issue with the following minimal reproduction code. After disconnecting from WiFi, setting WiFi.mode(WIFI_OFF), and using digitalWrite(23, LOW) (GP23: Wi-Fi module power) to turn off the WiFi chip power, the subsequent reconnect attempt fails. The issue specifically arises when trying to reinitialize the WiFiClient and reconnect to the WiFi network.

Steps to Reproduce

1. Connect to WiFi successfully.
2. Disconnect WiFi using WiFi.disconnect() and turn off the WiFi chip power using digitalWrite(23, LOW).
3. Attempt to reconnect by re-enabling power with digitalWrite(23, HIGH) and calling WiFi.begin(ssid, password) again.
4. Try to reinitialize and use a WiFiClient to connect to a server.

Expected Behavior

The WiFi chip should reconnect to the network, and WiFiClient should be able to establish a connection to the server.

Actual Behavior

The reconnection process fails, and WiFiClient cannot establish a new connection.

Reproduction Code

#include <Arduino.h>
#include <WiFi.h>

// WiFi Settings
const char* ssid = "SSID";
const char* password = "PASSWORD";

WiFiClient client;

void connectToWiFi();
void reconnectWiFiAndClient();
void disconnectWiFi();

void setup() {
  Serial.begin(115200);

  // Initial WiFi connection
  connectToWiFi();

  // Test communication with WiFiClient
  if (client.connect("example.com", 80)) {
    Serial.println("Connected to server!");
    client.println("GET / HTTP/1.1");
    client.println("Host: example.com");
    client.println("Connection: close");
    client.println();
    delay(1000);
    while (client.available()) {
      String line = client.readStringUntil('\n');
      Serial.println(line);
    }
    client.stop();
  } else {
    Serial.println("Connection to server failed.");
  }

  // WiFi disconnection process
  disconnectWiFi();
  
  // Reconnection process
  reconnectWiFiAndClient();
}

void loop() {
  // No specific tasks in the main loop
}

// Function to connect to WiFi
void connectToWiFi() {
  Serial.print("Connecting to WiFi");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected.");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
}

// Function to disconnect WiFi and turn off WiFi chip power
void disconnectWiFi() {
  Serial.println("Disconnecting WiFi...");
  client.stop();                   // Stop WiFiClient connection
  WiFi.disconnect();               // Disconnect WiFi
  delay(100);                      // Wait a bit
  WiFi.mode(WIFI_OFF);             // Turn off WiFi mode
  delay(100);                      // Wait a bit
  digitalWrite(23, LOW);           // Turn off WiFi chip power
  Serial.println("WiFi disconnected and power to WiFi chip is off.");
}

// Function to reconnect WiFi and WiFiClient
void reconnectWiFiAndClient() {
  digitalWrite(23, HIGH);          // Turn on WiFi chip power
  delay(100);                      // Wait for stabilization
  Serial.println("Reconnecting WiFi...");
  WiFi.mode(WIFI_STA);             // Set WiFi mode to STA
  connectToWiFi();                 // Reconnect to WiFi

  // Reuse WiFiClient after reconnection
  if (client.connect("example.com", 80)) {
    Serial.println("Reconnected to server!");
    client.println("GET / HTTP/1.1");
    client.println("Host: example.com");
    client.println("Connection: close");
    client.println();
    delay(1000);
    while (client.available()) {
      String line = client.readStringUntil('\n');
      Serial.println(line);
    }
    client.stop();
  } else {
    Serial.println("Reconnection to server failed.");
  }
}

Additional Information

Board: Raspberry Pi Pico W
PlatformIO Framework: Arduino
Library: None

When the code related to WiFiClient is removed, the reconnection process works as expected.
It would be great to know if this is a bug or if there is a missing step in the process for properly reinitializing the WiFi chip and WiFiClient.

Thank you!