Serial consoles and remote GDB

Rob Deker deker at slackdot.org
Sun Aug 29 15:13:35 PDT 2004


Hi folks,

 New to the list, so please bear with me if this is a question that's
been answered someplace before. I've been searching and can't seem to
find an answer.

I'm doing some driver hacking w/ FreeBSD 5.2.1 and I've hit a spot where
my life would be much easier if I had remote GDB for kernel debugging. I
am however using a serial console on this box, and can't seem to get
things working so that I have console access to the box on one serial
port and remote gdb running on the other one. Is this possible? I've
tried various combinations of port flags for sio[01] in the device.hints
file, but I'm not having much luck. I've tried toe following
combinations (with the following results):

 - hint.sio.0.flags="0x10"
   hint.sio.1.flags="0x80"
   
   This yeilded a console initially at boot, but one I told the loader
to go ahead and boot the kernel, all I got for output were repeated 0x8e
chars (looks like an accented capital 'A').

so, i figured that it might possibly be that the lowest numbered port
should be the one with 0x80 set in flags, so I tried:

 - hint.sio.0.flags="0x80"
   hint.sio.1.flags="0x10"

   This got me (again) a console up until kernel load, but after that I
had NO output at all.

I'm open to any suggestions. My problem is that the machines that are
the debug target and debug host are in my basement headless while my
office is upstairs and I really would like to avoid running up and down
stairs every time I need to switch in and out of gdb mode in ddb (no
matter how much I might need the exercise ;)

Thanks,

-d

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