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From: amos@taux01.UUCP (Amos Shapir)
Newsgroups: comp.unix.wizards
Subject: Re: Killing the printer daemon
Message-ID: <342@taux01.UUCP>
Date: Fri, 25-Sep-87 09:59:30 EDT
Article-I.D.: taux01.342
Posted: Fri Sep 25 09:59:30 1987
Date-Received: Sun, 27-Sep-87 01:32:01 EDT
References: <2419@drivax.UUCP> <8707@mimsy.UUCP>
Reply-To: amos%taux01@nsc.com (Amos Shapir)
Distribution: world
Organization: National Semiconductor (Israel) Ltd. Home of the 32532
Lines: 24
Hdate: 2 Tishrei 5748


You did not say what type of tty hardware you use, but this problem usually
happens on tty line drivers that wait for carrier signal on input -
since the driver expects to be sleeping for a short time, it sleeps
at a negative priority, which is virtually un-killable.

Some solutions:
Off Line:
* BSD kernels have a compilation-time flag for a 'soft carrier' flag that
 insures that the driver will never wait for hardware carrier bit;
* Fix the tty driver so its logic fits the hardware.

On Line:
* Connect a terminal at the printer's end and watch lpr empty out on the
 screen;
* Hack /dev/kmem to make the driver think the required bit is on (wizards
 only);
* Reboot.

I hope that helps.
-- 
	Amos Shapir			(My other cpu is a NS32532)
National Semiconductor (Israel)
6 Maskit st. P.O.B. 3007, Herzlia 46104, Israel  Tel. +972 52 522261
amos%taux01@nsc.com (used to be amos%nsta@nsc.com) 34 48 E / 32 10 N