Hi,

-----------------------------------------
[EMAIL PROTECTED]:~# cu -l /dev/ttyS0 -s 19200
Connected.
cu: Got hangup signal

Disconnected.
-----------------------------------------

I'm giving up on this one. I wanted to test things a bit more
methodically this morning, and have since then run into every
conceivable deadlock (can't install OpenBSD on laptop because it won't
boot off CD, can't install Ubunut 7.04 Server on PC for unknown reasons,
and more...).

To round things up, first a few errata from my previous emails:
- Ubuntu version was 7.04, not 6.10
- "comBIOS fails, while OpenBSD boot loader and kernel don't" should
  read: "comBIOS and OpenBSD boot loader fail, while OpenBSD kernel
  doesn't".

After all the hangup signal also occurred while pressing Enter at the
boot prompt. And it obviously makes sense that the boot loader would use
the system BIOS for console access.


Here's an overview of when things go wrong and not, as far as I could
test it:

Local                       Remote           Problem?
laptop/Ubuntu/cu            comBIOS          yes
laptop/Ubuntu/minicom       comBIOS          no
PC/OpenBSD/cu               comBIOS          no
ALL                         OpenBSD          no


Apparently it's something between Ubuntu's 'cu' and the Soekris comBIOS.
I've never had trouble with previous Ubuntu 'cu' versions.

The fact that I suddenly can't boot the laptop from CD suggests that
there is a hardware problem after all, like a broken off soldering pad
where the serial port connector is attached to the motherboard (it has
been traveling quite a lot lately, and it might have met the limits of
its collision resistance). Still it seems that all combinations listed
above find a way around any anomaly in the communication, but this one
doesn't.

I'm still curious about what the comBIOS does with the UART that OpenBSD
doesn't (or vv), but I've otherwise quite had it with this little
mystery, so I'll leave it for what it is and just use the PC for
accessing my Soekris boxens.


Bill



On Mon, 2007-10-22 at 23:27 +0200, Bill Maas wrote:
> Hello The Fungi,
> 
> everything works fine with cu(1) on OpenBSD 4.0. Still the whole thing
> has left me with a few questions.
> 
> I'm sure that there wasn't a problem with the net4801 the first time I
> tested, but now there is as well as with the net5501. The net5501 never
> worked with ubu 6.10. It looks like things go wrong most of the time,
> but not all of the time, and that it has been getting worse in the
> course of today. But that's hard to tell on hindsight, the first time I
> was just trying out different things, with little structure.
> 
> The "works sometimes" behaviour would suggest a hardware failure, e.g. a
> worn out serial port connector on the laptop. But then why does
> everything always work as expected once OpenBSD has taken over? What
> does the comBIOS do with the USART that the OpenBSD boot loader and
> kernel don't? And, is there a way to make the comBIOS act the same as
> the OpenBSD software?
> 
> Apparently a "hangup signal" here refers to an RS232 hangup signal
> "caused by a drop of DCD voltage by the modem"
> (http://www.linuxselfhelp.com/HOWTO/Modem-HOWTO-12.html).
> I can't see what a Soekris box has to do with the DCD line, however.
> 
> I'll test it some more the next days, see if anything interesting turns
> up. And I'm very curious to hear from the experts on this one.
> 
> Bill
> 
> On Mon, 2007-10-22 at 19:13 +0000, The Fungi wrote:
> > On Mon, Oct 22, 2007 at 08:11:57PM +0200, Bill Maas wrote:
> > > I was wrong: more systematic testing revealed that the same thing
> > > occurred with the net4801 as well. So it looks like either
> > > cu 1.07-19ubuntu1 on Ubuntu 6.10 is broken, or my only laptop with a
> > > serial port is slowly falling apart (can't find out which is the problem
> > > right now due to no PC with 6.10, and no time for installing it). Hasn't
> > > anyone else had this problem with U6.10?
> > [...]
> > 
> > Have you tested with another terminal emulator (screen, ckermit) to
> > rule out your hardware and pinpoint cu itself as the issue?
-- 
"Ask not what it's for, ask what you can do with it."

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