Subject: Re: unexpected halt of system while trying to print
To: Chris G. Demetriou <>
From: Martin Heller <>
List: port-alpha
Date: 03/06/1998 12:10:50
On Thu, 5 Mar 1998, Chris G. Demetriou wrote:

> > After a fresh install of NetBSD-1.3 I found a real unexpected behaviour:
> >
> > I'm using an AS200 with 64MB ram , S3-Trio VGA console. In order to build
> > a specific kernel, I wanted to print the file where all options for alpha
> > are listed. printcap was not set up properly so I did a simple
> >  'cat ALPHA > /dev/lpt0' ... whoa ! after 1 second the system was brought
> > to SRM console prompt.
> > The kernel? wrote : halted CPU 0
> >                     halt code = 2
> >                     kernel stack not valid halt
> >                     PC=18a98
> > any idea what went wrong?
> Interesting!!!  This this repeatable?

Yes !!! always the same ... 

> Problems have been reported like this on the i386 (dating back ... a
> while now) occasionally, but no solution has ever been found.

> I assume this is with the standard lpt configuration (interrupt
> driven).  You might see if the problem occurs if you use the driver's
> polling mechanism (remove the 'irq N' from your kernel config line for
> the lpt0 device).

I'll try that, but I haven't got the original 1.3 sources. The ones I've
got are a more recent.

> examining the registers with the SRM 'examine' command might give some
> useful information on where the crash happened, but i'd not bet too
> much on it.  8-)
I'll do that.Can I trace 'cat anyfile > /dev/lpt0 ' with a trace facility?

> Unfortunately, i've never had a device that I could attach to any of
> my machine's parallel ports to see if i could experience the problem
> myself.

Perhaps other folks should try the parallel ports too  ...