DFS + CONFIG_ESP32_RTC_CLK_SRC_INT_8MD256=y causes reading ADC hang (IDFGH-6499)

[AxelLin]

Environment

• Module or chip used: ESP32-WROOM-32E
• IDF version: v4.3.2-106-g8a7b2f326b
• Build System: idf.py
• Compiler version: xtensa-esp32-elf-gcc (crosstool-NG esp-2021r2) 8.4.0
• Operating System: Linux
• Power Supply: USB

Problem Description

DFS + CONFIG_ESP32_RTC_CLK_SRC_INT_8MD256=y causes reading ADC hang

Steps to reproduce

Use examples/wifi/power_save snip code to reproduce the issue:

1. Set ESP32_RTC_CLK_SRC_INT_8MD256=y
2. Add below code for reading adc1

diff --git a/examples/wifi/power_save/main/power_save.c b/examples/wifi/power_save/main/power_save.c
index 4ad924665c..2d4a985165 100644
--- a/examples/wifi/power_save/main/power_save.c
+++ b/examples/wifi/power_save/main/power_save.c
@@ -19,6 +19,7 @@
 #include "esp_event.h"
 #include "esp_pm.h"
 #include "nvs_flash.h"
+#include "driver/adc.h"
 
 /*set the ssid and password via "idf.py menuconfig"*/
 #define DEFAULT_SSID CONFIG_EXAMPLE_WIFI_SSID
@@ -81,6 +82,19 @@ static void wifi_power_save(void)
     esp_wifi_set_ps(DEFAULT_PS_MODE);
 }
 
+static void test_adc(void)
+{
+    int adc_val;
+    adc1_config_width(ADC_WIDTH_BIT_12);
+    adc_gpio_init(ADC_UNIT_1, ADC1_CHANNEL_0);
+    adc1_config_channel_atten(ADC1_CHANNEL_0, ADC_ATTEN_DB_11);
+
+    vTaskDelay(pdMS_TO_TICKS(50));
+
+    adc_val = adc1_get_raw(ADC1_CHANNEL_0);
+    ESP_LOGI(TAG, "ADC val: %d", adc_val);
+}
+
 void app_main(void)
 {
     // Initialize NVS
@@ -111,5 +125,7 @@ void app_main(void)
     ESP_ERROR_CHECK( esp_pm_configure(&pm_config) );
 #endif // CONFIG_PM_ENABLE
 
+// Test reading adc
+     test_adc();
     wifi_power_save();
 }

3. build the power_save and run
   Then observe device hang at below:
   ...
   I (590) cpu_start: Starting scheduler on PRO CPU.
   I (0) cpu_start: Starting scheduler on APP CPU.
   I (877) pm: Frequency switching co

Also note comment out below code can make CONFIG_ESP32_RTC_CLK_SRC_INT_8MD256=y work.
https://github.com/espressif/esp-idf/blob/release/v4.3/components/esp_hw_support/port/esp32/rtc_sleep.c#L196-L202
Looks like 73384ad is the bad commit.

[AxelLin]

BTW, when I test DFS + wifi, sometimes I got below error message:

E (19377) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 40000000Hz
E (28126) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 40000000Hz

Does that mean something wrong in my configuration?
Or I can just ignore it? (The device seems still working)

[negativekelvin]

#8089

[AxelLin]

#8089

Above PR fixes the issue, thanks.

[AxelLin]

BTW, when I test DFS + wifi, sometimes I got below error message:

E (19377) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 40000000Hz E (28126) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 40000000Hz

Does that mean something wrong in my configuration? Or I can just ignore it? (The device seems still working)

I found the device shows below messages today:
E (36759743) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 80000000Hz
E (37138888) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 80000000Hz
E (37233375) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 80000000Hz
E (37354657) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 40000000Hz
E (37577531) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 80000000Hz

I'm confused, isn't 80MHz == 80000000Hz?

[AxelLin]

BTW, when I test DFS + wifi, sometimes I got below error message:

E (19377) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 40000000Hz E (28126) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 40000000Hz

Above message only happens on v4.3 branch, it does not happen on v4.4 or master tree.
#8162 (comment) fixes above error message on v4.3.

Edit: 496f2a5 fixed above error message on v4.3.

[esp-lis]

BTW, when I test DFS + wifi, sometimes I got below error message:

E (19377) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 40000000Hz E (28126) wifi_apb80m_request: WiFi needs 80MHz APB frequency to work, but got 40000000Hz

Does that mean something wrong in my configuration? Or I can just ignore it? (The device seems still working)

I summarize the commits that fix this issue on 4.1, 4.2, 4.3, 4.4 as follows:
4.4 or master: 75a1942
4.3 ae84265
4.2 ebee6f3
4.1 2ed9685

[Alvin1Zhang]

Thanks for reporting, feel free to reopen.

[AxelLin]

The #8152 (comment) fixes the error mesage.
However it still hang unless applying #8089 .

[AxelLin]

@Alvin1Zhang @esp-lis
It's fine to close this one and trace #8007 instead.
However, nobody responses with #8007 .