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To: Peter Dufault <dufault@hda.com>
cc: mdean@best.com (mdean), freebsd-hackers@FreeBSD.ORG
Subject: Re: Opinions wanted. 
In-reply-to: Your message of "Sat, 18 Oct 1997 19:13:30 -0400."
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Date: Sun, 19 Oct 1997 17:16:20 +0930
From: Mike Smith <mike@smith.net.au>
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> > If an 8255 (digital I/O) 8-bit port is opened via open() call by the user
> > as O_RDWR then it becomes an output, 

It makes little sense to model the 8255 like this.  It would be much 
more sensible to allow open/close and require an ioctl to provide 
register access.

> The system design must arrange to pull the signals high at start
> up (if you can, yes I'm mostly software) so that it doesn't turn
> on devices.

This is impossible with the 8255, as it resets its outputs low whenever 
the mode byte is changed.  It is a most disgusting device indeed.

mike