m...@netbsd.org (Emmanuel Dreyfus) writes: >I understand kprintf operates at IPL_HIGH, while the USB subssytem >processes I/O at IPL_SOFTCLOCK. Does that mean I just cannot rely >on USB for console output?
It can only work if USB is used in polling mode, which usually also means that you must not use that USB controller for anything else. An alternative on some USB controllers is the Debug Capability Interface. That feature has little to do with USB but is more like a low level serial communication on a dedicated port... https://indico.bsdcan.org/event/1/contributions/22/
