Serial console trouble: loader and login works, but no kernel messages

Tim Judd tajudd at gmail.com
Sun Aug 23 18:25:58 UTC 2009


On 8/23/09, Thomas Backman <serenity at exscape.org> wrote:
> First off: Not subscribed to this list, please make sure to Cc me if
> you don't reply directly. :)
>
> Anyway, I finally got my null modem cable, and plugged in in between a
> machine running 8.0-BETA2 and one running WinXP using Hyperterminal.
>
> My settings:
>
> /boot/loader.conf:
> boot_multicons="YES"
> boot_serial="YES"
> comconsole_speed="115200"
> console="comconsole,vidconsole"
>
> /etc/ttys:
> # Serial terminals
> # The 'dialup' keyword identifies dialin lines to login, fingerd etc.
> ttyu0   "/usr/libexec/getty std.115200" vt100   on secure
>
> /boot.config (which is read properly):
> -Dh -S115200
>
> Anything wrong in the above?
> Hyperterminal is set to 115200 bps, 8 bits, no parity, 1 stop bit, and
> no flow control (if that's the correct translation to English).
>
> On the serial console, I go from the screen with the FreeBSD logo,
> with single-user options etc. (which works fine), and then nothing,
> until a login tty pops up (which also works fine). The main, if not
> only, reason I want a serial console is to be able to use it for
> single user mode, DDB, and so on.
> All kernel messages, and all rc messages are seen only on the graphics
> card; the serial console receives nothing but the "/boot.config: -
> Dh ...", the logo screen, and then the login screen, during startup
> and *nothing* at all during shutdown. Also, I'm able to login and use
> the system both via the serial console and via the graphics card/
> keyboard... Is this supposed to be? I'm not complaining, I just got
> the impression it was one or the other.
>
> Any advice on how to get the kernel/rc messages etc. to the serial
> console (only or as well)?
>
> Regards,
> Thomas


Do you use the VGA/vidconsole at all?

A serial-only device (think soekris, ALIX/WRAP boards) that has no VGA
will have different requirements than a serial-only device will.

Your loader.conf statements are different than mine in the definition
that you have more than I do to enable serial.

My loader.conf just has one statement:
  console="comconsole"  - to feed ALL bootloaders, kernel probing, rc
startup on the serial device.  /etc/ttys defines the login lines.

Though trial and error, I found when you use a dual-setup:
"comconsole,vidconsole", the first one (comconsole) will get rc
output, and vidconsole won't.

Of course, you're on 8.0 and I don't run BETAs.  So the 8.0 BETA might
still be having com port oddities, plus I noticed your ttys line is
ttyu0, not ttyd0.  Did 8.0 change the serial line device?



To enable a serial-only device in my setups:
/boot/loader.conf:
  console="comconsole"

/boot.config:
  -D

/etc/ttys:
# enable serial line, cons25 or vt100, depending if I'm originating
from a bsd or windows box.



Enabling dual-setups should be just the loader.conf change to dual console.


HTH


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