Subject: Behavior of DTR changed between 1.3.3 and 1.4.1?
To: None <port-sparc@NetBSD.ORG>
From: Greg Earle <earle@isolar.DynDNS.ORG>
List: port-sparc
Date: 09/23/1999 14:06:17
I'm using a serial console on my SPARCstation 20 here at home.
The serial port is attached to my G3 Mac, and I use ZTerm on the Mac to
talk to the SPARCstation 20 console.

When I originally brought the machine up, it was with 1.3.3 installed on a
borrowed disk, taken from my work machine configuration.

I recently installed 1.4.1 fresh on a new 9 Gb disk that's now my system disk.

What I noticed was that back under 1.3.3, I could reboot the Mac (which I
often have to do, given that it's a Mac after all  (-: ) and pop up ZTerm
and there would be my SPARCstation, unaffected by it all.  I was pleasantly
surprised that this was the case.

Now, under 1.4.1, that's no longer true.  I was finding that if I had to
power-cycle the Mac, or even just reset it via the Control-Command-Power
3-fingered salute, upon coming up, if I ran ZTerm I'd find my SPARCstation
dropped to the "ok " PROM prompt.  That was bad enough, but in addition a
"go" did not resume - it yielded a "hex #80 address error" or somesuch weird
diagnostic and I'd have to reboot.  Needless to say, this was rather alarming.

I think I've found a workaround, namely I pull the serial cable out of the
Mac before restarting/3-finger saluting to reboot it.  When I plug it back in
after the Mac is up, all is well and the SS20 is not at the PROM prompt.
But I'd really rather not have to remember that every time - especially if
the Mac ever does a spontaneous reboot.

But that makes me curious - shouldn't plugging the cable back in to the Mac
have the same effect, i.e. presumably dropping DTR and then raising it,
and cause the SS20 to drop to the PROM again?  I'm assuming that a DTR drop
during the Mac reboot/reset is what caused the Break to be generated to drop
the SS20 to the PROM in the first place.

I'm interested to know how the behaviour changed between 1.3.3 and 1.4.1,
and if there's some way I can override it and get the old behavior back.
I'd far rather have the Sun ride out any Mac reboots while still connected
to it like it used to.  If I want to "break" it down to the PROM, I'd rather
be able to do that manually via Command (Apple)-B inside ZTerm.

Thanks for any hints,

	- Greg