Re: BeagleBone Black doesn't boot without serial console (10.0 release)

On Fri-11-Oct-2024 18:22, Martin Husemann wrote:
> On Fri, Oct 11, 2024 at 05:33:21PM +0200, Dr. Nicola Mingotti wrote:
>> I will see, probably better i conclude this project with a RPi3B+ where i
>> accumulated already more experience in NetBSD,
>> i also found other surprises about GPIO with BBB, i will say in another
>> message.
> No, it is a plain setup issue. Build your own kernel either witout
> ddb or with the console magic changed. You can create a "GENERIC64.local"
> file with
>
> 	no options DDB
>
> or if you want to keep ddb but disable the serial break to enter it
>
> 	options CNMAGIC="+++++"
>
> and all will be fine.
>
>
> Martin

Thank you Martin and all people who have given me suggestions,
I will try them in the weekend if children and wife permit.

Anyhow, i made some more experiments which i think clarify
even my previous observation. Basically (as probably somebody
already stated, i red very quickly) pluggin-in or pulling-out the
J1-UART (serial cable for friends)  calls the debugger. Which
of course is not desirable, but can explain what i saw in the
afternoon.

Last experiments below:

=====================

=== CASE-1 ====
0. the device is working, booted without serial
1. i login with sssh
2. connect the serial (by serial i mean that UART that is plugged in the 
J1 connector)
2.. ssh hangs
2.. serial shows the 'db{0}>' prompt
(*) 3. i remove the serial
4. remove the power plug
5. put int the power plug
6. wait a bit
7. ping and ssh work

=== CASE-2 ===
0. the device is working booted the device with serial
1. i login with sssh
(*) 3. remove the serial
4. ssh hangs
5. remove power jack
6. insert power jack
7. wait a bit
8. i can ssh to the machine

=== POSSIBLE EXPLANATION OF FIRST OBSERVED BEHAVIOUR =======

---- in my first post i wrote -----
If i remove the searial console from the J1
and i poweroff + remove power + give power, the boot stops,
i reconnect the serial console and i see this:
(*) ... debugger ...
-----------------------------------

After the last experiments i think that what happened in
my first experiments is this:

. When i powered the device probably the device was busy doing
   some checks, maybe filesystem.

. Since i was not able to login via ssh then i connected the
   serial console

. But inserting or removing the serial console opens the debugger.

=====================

good night

nicola