Date: Fri, 13 Dec 1996 20:22:40 +1100 From: Bruce Evans <bde@zeta.org.au> To: hackers@freebsd.org, suttonj@interconnect.com.au Subject: Re: My Banksia Internal Modem - sio driver Message-ID: <199612130922.UAA27331@godzilla.zeta.org.au>
next in thread | raw e-mail | index | archive | help
>(after numerous reboots) and sometimes not. So I did some searching of the >mail archives and realised that I should use the 0x80 flag to see what was >happening (should have read the sio man page...). I suddenly found that it >was failing consistently on the 6th probe: > >/kernel: sio1: probe test 6 failed > >Thinking I had nothing to loose I then changed the source for sio so that >the sixth probe always returned a successful result. So far I haven't had >any problems more internal modem problems or problems with my other 3 >serial ports. Device drivers are definitely way above my level of >programming skill so what I'm wondering is - Is it likely that I may >create any other problems by doing this? It depends. Failure 6 without failure 5 says that the interrupt went away before it really went away :-). The interrupt handler uses the "real" interrupt bit to decide whether it should loop looking for more things to do. Looping once or twice only adds 5-10% to the serial overhead. >Could adding extra DELAY >statements achieve a similar result more cleanly?? There's already a huge delay of 1000 usec that covers test 6. You might learn how long the interrupt takes to really go away. I guess it doesn't go away. Looping in the interrupt handler for one or two multiples of 1000 usec would increase serial overhead by a large factor. Bruce
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199612130922.UAA27331>