Workaround for using wifi module on S2 with USB-CDC console.

components/modules/wifi.c

@@ -34,6 +34,7 @@
 #include "lauxlib.h"
 #include "lextra.h"
 #include "wifi_common.h"
+#include "task/task.h"
 
 static int wifi_getmode (lua_State *L)
 {
@@ -92,7 +93,21 @@ static int wifi_stop (lua_State *L)
     0 : luaL_error (L, "failed to stop wifi, code %d", err);
 }
 
+#if defined(CONFIG_ESP_CONSOLE_USB_CDC)
+// For some unknown reason, on an S2 with USB CDC console enabled, if we allow
+// the esp_wifi_init() to run during initial startup, something Bad(tm)
+// happens and the S2 fails to enumerate on the USB bus. However, if we defer
+// the wifi initialisation, it starts up fine. This is an ugly workaround, but
+// I'm out of ideas at this point. If I use a UART console, I see no errors
+// even with the immediate init.
+static task_handle_t th;
+#endif
 
+static void do_esp_wifi_init(task_param_t p, task_prio_t)
+{
+  wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+  ESP_ERROR_CHECK(esp_wifi_init (&cfg));
+}
 
 extern void wifi_ap_init (void);
 extern void wifi_sta_init (void);
@@ -101,10 +116,13 @@ static int wifi_init (lua_State *L)
   wifi_ap_init ();
   wifi_sta_init ();
 
-  wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+#if defined(CONFIG_ESP_CONSOLE_USB_CDC)
-  esp_err_t err = esp_wifi_init (&cfg);
+  th = task_get_id(do_esp_wifi_init);
-  return (err == ESP_OK) ?
+  task_post_low(th, 0);
-    0 : luaL_error (L, "failed to init wifi, code %d", err);
+#else
+  do_esp_wifi_init(0, 0);
+#endif
+  return 0;
 }