WiFi.setSleepMode(WIFI_LIGHT_SLEEP) dies on 2.4.1 after a few seconds

[errolt]

Basic Infos

• This issue complies with the [issue POLICY doc]
• I have read the documentation at readthedocs and the issue is not addressed there.
• I have tested that the issue is present in current master branch (aka latest git).
• I have searched the issue tracker for a similar issue.
• If there is a stack dump, I have decoded it.
• I have filled out all fields below.

Platform

• Hardware: NodeMCU V0.9
• Core Version: latest, might be 68f04bc
• Development Env: Arduino IDE
• Operating System: Windows

Settings in IDE

• Module: Nodemcu 0.9
• Flash Mode: ?
• Flash Size: 4MB
• lwip Variant: v2 Lower Memory
• Reset Method: nodemcu
• Flash Frequency: 40Mhz
• CPU Frequency: 80Mhz
• Upload Using: SERIAL
• Upload Speed: 256000

Problem Description

Adding WiFi.setSleepMode(WIFI_LIGHT_SLEEP); to Setup() "crashes" Loop() in a way. Loop() stops running, or perhaps Delay never returns. Tested the same sketch against 2.4.0 and it runs fine. Never "dies".

MCVE Sketch

#include <ESP8266WiFi.h>

const char* ssid     = "OpenWrt3";
const char* password = "";

void setup() {
  Serial.begin(115200);
  WiFi.setSleepMode(WIFI_LIGHT_SLEEP);
  delay(10);

  // We start by connecting to a WiFi network

  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  
  /* Explicitly set the ESP8266 to be a WiFi-client, otherwise, it by default,
     would try to act as both a client and an access-point and could cause
     network-issues with your other WiFi-devices on your WiFi-network. */
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

int value = 0;

void loop() {
  delay(1000);
  Serial.println("Delay");
    
  }

Debug Messages

SDK:2.2.1(cfd48f3)/Core:win-2.5.0-dev/lwIP:2.0.3(STABLE-2_0_3_RELEASE/glue:arduino-2.4.1)
sleep enable,type: 1
wifi evt: 2


Connecting to OpenWrt3
sta config unchangedscandone
scandone
state: 0 -> 2 (b0)
state: 2 -> 3 (0)
state: 3 -> 5 (10)
add 0
aid 4
cnt 

connected with OpenWrt3, channel 6
dhcp client start...
wifi evt: 0
.ip:192.168.1.17,mask:255.255.255.0,gw:192.168.1.1
wifi evt: 3
.
WiFi connected
IP address: 
192.168.1.17
Delay
Delay
Delay
Delay
Delay
Delay
Delay
Delay
Delay
pm open,type:1 0

After this there is no more "Delay" prints, takes 10 to 12 seconds before silence. With 2.4.0 the "Delay" prints continue indefinitely.

This is what 2.4.0 gives me:

wifi evt: 2


Connecting to OpenWrt3
wifi evt: 0
wifi evt: 3
.
WiFi connected
IP address: 
192.168.1.17
Delay
Delay
Delay
Delay
Delay
Delay
Delay
Delay
Delay
pm open,type:1 0
Delay
Delay
Delay
Delay
Delay

[reloxx13]

same here, even with latest git framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910

[MikhailNatalenko]

I'm comfirming this bug! Guys, we need LIGHT_SLEEP_T

[reloxx13]

20 April and this just got completly ignored.

I dunno, do you guys all have free energy or why u give a fu* on this???

[reloxx13]

Same for Alexa Workaround/Losing Post Data when no header set.

[MikhailNatalenko]

@reloxx13

I suppose, it is a low level feature from SDK. It was never been supported as well, so...

Maybe @igrr can tell as more info about this super sad bug.

[d-a-v]

This seems to be a bug inside the SDK itself.
What you could try is

• WIFI_NONE_SLEEP
• PingAlive (link)
• the latest SDK updates with yet undocumented sleep API (update to latest git version of nonos-sdk (SDK:3.0.0-dev(c0f7b44)) #4806)

[errolt]

Fix by #5210