Hi all,
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.
In ath_tx_start_dma function,
bf = 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 it, thanks.
Any help will be appreciated !
Best & Regards

John Green