I have met a problem that
devices can not transmit any frames after serveral hours just in STA mode. I find that when
it happens, I can not get wbuf from sc->sc_txbuf.
TAILQ_FRIST(&sc->sc_txbuf), the bf is NULL.
but it is hard to
find the true cause that we can not get wbuf any more, even
I find where we return the wbuf to sc->sc_txbuf.
I want to know how to debug
Any help will be appreciated