Closed
Description
There is a USB interface issue, that the USB interface locks up if input symbols arrive too fast AND are echoed back. In the master branch, this is hard to replicate. The Issue got evident with #8520, where the issues can re reproduced easily.
When the USB interface seems to be locked up, the board continues to work. Analysis in the Debugger shows, that input symbols still arrive and are processed. Output to commands will be created and the function mp_hal_stdout_tx_strn() is called, which in turn calls tud_cdc_write() and tud_cdc_write_flush(). Only the data does not arrive at the connected PC/USB interface.