Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!jarthur!bridge2!3comvax!tymix!cirrusl!news
From: news@cirrusl.UUCP (USENET News System)
Newsgroups: comp.unix.wizards
Subject: tty driver strange problem
Message-ID: <1383@cirrusl.UUCP>
Date: 28 Feb 90 22:09:56 GMT
Reply-To: saeed@sunseeker (Saeed Talebbeik)
Distribution: all
Organization: Cirrus Logic Inc.
Lines: 11

I am writing a tty driver for a multiport intelligent serial card under SCO
XENIX SYSTE. My test case for transmit is very simple. I try to "cat" a file
of 1 Mb size and redirect the output to the 8 ports at the same time in the
background "cat filename > /dev/port[1-8] &". The problem is an elusive bug.
Every now and then the processes go to sleep on some channel and the whole
test freezes up. I have increased the number of system clists from 100 to 1000.
That did not solve the problem either. The xon/xoff handshaking is done automatically by the board and the driver does not have to handle that. Does anybody 
know any debugging hints to trace the problem. I would like to know if I can
find out what those channel numbers which te processes are sleeping mean? 
Does this look like a driver or a hardware problem ? Any comments or help
is very appreciated.     Thanks.