Date: Fri, 08 Feb 2002 14:46:21 +0100 From: Titus von Boxberg <titus@bhi-hamburg.de> To: "freebsd-hackers@FreeBSD.ORG" <freebsd-hackers@FreeBSD.ORG> Subject: tcdrain won't work? Message-ID: <3C63D6AD.475263AC@schuett-inhouse.de>
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Hi, I tried to use tcdrain to make sure that all characters are sent via a COM port but it seems that it won't work in about 50% of the calls to it, i.e. tcdrain returns before all characters are sent via sio.c. Has anyone noticed that effect? I tried to understand how it works. Apparently tty.c operates in ttywait() and ttwwakeup() on the output queue size in tp->t_outq.c_cc and TS_BUSY in tp->t_state (?). I can't find any piece of code filling tp->t_outq.c_cc with other values than 0. And sio.c seems to not set TS_BUSY in tp if outq.c_cc is not 0. Is it simply unimplemented or have I missed the point? Thanks in advance! Titus To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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