Useful option to add to ESP IDF - do flash writes from worker task. (CON-1518)

[jonsmirl]

You can't do flash writes from tasks which have their stack in PSRAM. That's just a limitation of the ESP architecture. The work around for this is to make a worker task with a small stack in internal RAM and then queue the writes to this worker task.

The trouble with this is that now I have to hunt down every place which is doing flash writes and then change the code to queue them to the worker task. How about giving me an option in the ESP IDF SPI flash driver to do flash writes from a worker task? Then the IDF will automatically modify everything which does flash writes.

This is not as simple as it seems, for example the flash write currently bothering me is inside the SPIFFS file system code. Since I don't want to modify SPIFFS now I have to move my file system calls into a worker task.