Update WiFiGeneric.cpp

[zhangyanjiaoesp]

Description of Change

Enlarge the cache_tx_buf num

Related links

Related PR in Arduino Lib: #5791

close espressif/esp-idf#8992

[CLAassistant]

All committers have signed the CLA.

[atanisoft]

this was added to reduce the memory footprint of the WiFi driver as it increased considerably from IDF v3 to IDF v4.

Refer to #5791 for this. @SuGlider fyi...

[SuGlider]

Yes... Default now is WiFi Dynamic Allocation in order to reduce HEAP consumption.
If the user wants to go with Static Allocation, the application shall use WiFiGenericClass::useStaticBuffers(true); before setting the WiFi Mode with WiFiGenericClass::mode()

[zhangyanjiaoesp]

@SuGlider Although the customers can call WiFiGenericClass::useStaticBuffers(true) to solve the problem, but I think we also need to change the value cfg.cache_tx_buf_num = 1 to at least 4, this will ensure the customers can send several packets at the same time.

[SuGlider]

OK, Agree. Please commit this change. This will cost 5K RAM in the heap. It is worth it.

[SuGlider]

@zhangyanjiaoesp -
Please try using the API that sets Static WiFi allocation:

void setup() {
  Serial.begin(115200);
  WiFi.useStaticBuffers(true);
  WiFi.mode(WIFI_STA);
  
  // rest of the necessary code ...
}

WiFi.useStaticBuffers(true); will force Arduino to use default sdkconfig WiFi setup:

CONFIG_ESP32_WIFI_STATIC_RX_BUFFER_NUM=8
CONFIG_ESP32_WIFI_DYNAMIC_RX_BUFFER_NUM=32
CONFIG_ESP32_WIFI_STATIC_TX_BUFFER=y
CONFIG_ESP32_WIFI_TX_BUFFER_TYPE=0
CONFIG_ESP32_WIFI_STATIC_TX_BUFFER_NUM=8
CONFIG_ESP32_WIFI_CACHE_TX_BUFFER_NUM=16

[SuGlider]

I reject this PR and changes.... as explained in
espressif/esp-idf#8992 (comment)
espressif/esp-idf#8992 (comment)

[SuGlider]

@zhangyanjiaoesp - Some background about the PR #5791:

At the time of this PR #5791, the idea was to free some heap space when WiFi was activated.

One possible solution, for the lack of heap, was to disable malloc over psram, as done in IDF 3.3, and then enable dynamic buffers in sdkconfig.

The PR #5791 was intended to find a way to keep psram malloc working and, at the same time, enable dynamic WiFi buffer allocation to free some heap memory. This combination was impossible due to a limitation imposed by KConfig.

This work around used in the PR was a nice suggestion from @igrr to try to override WiFi driver and kconfig limitation.
We implemented it and it is working for a number of Arduino users as of today. I don't see a real benefit in disabling it.

[SuGlider]

Thanks @zhangyanjiaoesp !