Date: Sun, 19 Oct 1997 17:16:20 +0930 From: Mike Smith <mike@smith.net.au> To: Peter Dufault <dufault@hda.com> Cc: mdean@best.com (mdean), freebsd-hackers@FreeBSD.ORG Subject: Re: Opinions wanted. Message-ID: <199710190746.RAA01382@word.smith.net.au> In-Reply-To: Your message of "Sat, 18 Oct 1997 19:13:30 -0400." <199710182313.TAA23016@hda.hda.com>
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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
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