Date: Thu, 6 Feb 1997 17:48:56 +1100 From: Bruce Evans <bde@zeta.org.au> To: hackers@freebsd.org, questions@freebsd.org, stesin@gu.net Subject: Re: Strange(!!) sio callin/callout behaviour in 2.1.6 Message-ID: <199702060648.RAA10833@godzilla.zeta.org.au>
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>I observe the following misbehaviours with regard to sio >driver: > >1. pppd never seems to receive/handle a SIGHUP from modem. Perhaps the modem never hangs up. >2. Callout devices behavior screwed... example: say I take the sio > unit 5, getty active on ttyd5, TR LED on modem is on, then: > > # stty -a -f /dev/ttyd5 > [...a screen of stty's output goes here, Ok...] > # stty -a -f /dev/cuaa5 > stty: /dev/cuaa5: Device busy > # cu -l /dev/cuaa5 -s 57600 > cu: /dev/cuaa5: Line in use > # This means that something has /dev/ttyd5 open. Perhaps getty succeeds in opening a few microseconds after pppd closes /dev/cuaa5. getty sleeps until carrier is present, but no longer, so if the port is shared between a getty and a dialout program like pppd and the dialout program closes the dialout port before carrier drops, then the getty will grab the port. HUPCL on the dialout port and a sufficiently large dtrwait should prevent this from happening if the modem responds to DTR dropping sufficent quickly. Bruce
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