cleanup

esphome/components/socket/__init__.py

@@ -126,13 +126,15 @@ def require_wake_loop_threadsafe() -> None:
     """Mark that wake_loop_threadsafe support is required by a component.
 
     Call this from components that need to wake the main event loop from background threads.
-
-    On ESP32: Uses FreeRTOS task notifications (<1 us, no socket needed).
-    On other platforms: Uses a shared UDP loopback socket mechanism (~208 bytes RAM).
+    This enables the shared UDP loopback socket mechanism (~208 bytes RAM).
+    The socket is shared across all components that use this feature.
 
     This call is a no-op if networking is not enabled in the configuration.
 
-    IMPORTANT: This is for background task context only, NOT ISR context.
+    IMPORTANT: This is for background thread context only, NOT ISR context.
+    Socket operations are not safe to call from ISR handlers.
+
+    On ESP32, FreeRTOS task notifications are used instead (no socket needed).
 
     Example:
         from esphome.components import socket

esphome/core/application.cpp

@@ -611,10 +611,7 @@ void Application::unregister_socket_fd(int fd) {
     if (i < this->socket_fds_.size() - 1)
       this->socket_fds_[i] = this->socket_fds_.back();
     this->socket_fds_.pop_back();
-#ifdef USE_ESP32
-    // Unhook the socket's netconn callback
-    esphome_lwip_unhook_socket(fd);
-#else
+#ifndef USE_ESP32
     this->socket_fds_changed_ = true;
     // Only recalculate max_fd if we removed the current max
     if (fd == this->max_fd_) {

esphome/core/lwip_fast_select.c

@@ -10,7 +10,7 @@
 // Thread safety analysis
 // ======================
 // Three threads interact with this code:
-//   1. Main loop task   — calls init, has_data, hook, unhook
+//   1. Main loop task   — calls init, has_data, hook
 //   2. LwIP TCP/IP task — calls event_callback (which reads s_original_callback, writes rcvevent)
 //   3. Background tasks — call wake_main_loop
 //
@@ -31,7 +31,8 @@
 //     the write), so it always sees the initialized value.
 //
 //   sock->conn->callback (netconn_callback, 4-byte function pointer):
-//     Written by main loop in hook_socket() and unhook_socket().
+//     Written by main loop in hook_socket(). Never restored — all LwIP sockets share
+//     the same static event_callback, so the wrapper stays in place permanently.
 //     Read by TCP/IP thread when invoking the callback.
 //     Safe: 32-bit aligned pointer writes are atomic on Xtensa and RISC-V (ESP32).
 //     The TCP/IP thread will see either the old or new pointer atomically — never a
@@ -133,17 +134,6 @@ void esphome_lwip_hook_socket(int fd) {
   sock->conn->callback = esphome_socket_event_callback;
 }
 
-void esphome_lwip_unhook_socket(int fd) {
-  struct lwip_sock *sock = lwip_socket_dbg_get_socket(fd);
-  if (sock == NULL || sock->conn == NULL)
-    return;
-
-  // Restore original callback. Atomic on ESP32 (32-bit aligned pointer write).
-  if (s_original_callback != NULL) {
-    sock->conn->callback = s_original_callback;
-  }
-}
-
 // Wake the main loop from another FreeRTOS task. NOT ISR-safe.
 void esphome_lwip_wake_main_loop(void) {
   TaskHandle_t task = s_main_loop_task;

esphome/core/lwip_fast_select.h

@@ -23,10 +23,6 @@ bool esphome_lwip_socket_has_data(int fd);
 /// Must be called from the main loop after socket creation.
 void esphome_lwip_hook_socket(int fd);
 
-/// Unhook a socket's netconn callback, restoring the original event_callback.
-/// Must be called from the main loop before closing the socket.
-void esphome_lwip_unhook_socket(int fd);
-
 /// Wake the main loop task from another FreeRTOS task — costs <1 us.
 /// NOT ISR-safe — must only be called from task context.
 void esphome_lwip_wake_main_loop(void);