ESP32 Forum

The ESP-IDF docs for CONFIG_SPIRAM_ALLOW_STACK_EXTERNAL_MEMORY state:

If you have a task that needs a large amount of stack and does not call on ROM code in any way (no direct calls, but also no Bluetooth/WiFi) ...

What does it mean that the task can "not call on ROM code in any way?"

Ok, thank you. From the page you linked:

ROM functions as not treated as public APIs

So does this mean I can call public API functions (e.g. esp_*) from a FreeRTOS task with a stack that is in external memory?

Yes, that should be safe. If not, then you can ask for help on github and report issue.