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Xref: sserve comp.os.386bsd.bugs:2625 comp.os.386bsd.questions:14553 Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!bunyip.cc.uq.oz.au!munnari.oz.au!news.Hawaii.Edu!ames!purdue!haven.umd.edu!news.umbc.edu!eff!news.kei.com!news.mathworks.com!udel!gatech!howland.reston.ans.net!math.ohio-state.edu!jussieu.fr!univ-lyon1.fr!ensta!bsd6.ensta.fr!loyer From: loyer@bsd6.ensta.fr (Frederic Loyer) Newsgroups: comp.os.386bsd.bugs,comp.os.386bsd.questions Subject: Re: PPP comments/observations NetBSD 1.0 Date: 8 Nov 1994 17:53:32 GMT Organization: Techniques Avancees, Paris Lines: 37 Message-ID: <39odus$k5a@ici-paris.ensta.fr> References: <39mk2p$f7@news.mic.ucla.edu> NNTP-Posting-Host: bsd6.ensta.fr In article <39mk2p$f7@news.mic.ucla.edu>, Scott Burris <scott@pita.cns.ucla.edu> wrote: > >First, my hardware configuration: >486DX2/66 ISA 8meg, IDE and Buslogic SCSI, 15550 serial ports, USR V.34 modem. >Modem talks to serial port at 57,600. ... > Secondly, I'm getting a few silo overflow messages every hour. Is >it known that NetBSD's com driver can't keep up at 57,600? Since the port >is set to do hardware handshaking, why am I getting the messages at all? >When the FIFO is full, doesn't the serial port hardware automatically >deassert CTS (or RTS, can't remember which one for this direction)? > The message "silo overflow" is printed when NetBSD doesn't read incoming characters fast enough. Some serial card provide automatic flow control to prevent data loss. IMHO, many other serial card do not provide it, and just copy the right bit from the modem contrl register to the RTS pin. Setting the port to do hardware handshaking (with 'stty crtscts') make NetBSD stop sending characters depending on the CTS signal, but do not seem to change RTS signal beacause of an overflow. The only solution seems to get a better serial card... or reducing the speed. With a 16450 (no FIFO) things are far worse: because of one interruption loss, NetBSD stop sending characters from the output queue, until pppd is killed. I'll send my patch to the netbsd-bugs mailing list. -- ___ ________ _ | Frederic Loyer | __\| _|_ _/ \ | Ecole Nationale Superieure | __\____ | |/ _ \ | de Techniques Avancees |___\_____|___/ \_\ | e-mail : loyer@ensta.fr