Subject: KGDB problem

From: [email-masked] (Patrick Hilt)
Date: Fri, 27 Jun 2003 14:11:18 -0400

Hello!
I just recently started working on Broadcom MIPS32 architecture (7115 chipset 
based STB, Broadcom modified 2.4.18 kernel) and have been trying to get kgdb 
setup to do some kernel source level debugging... with little success I might 
add ;-|. I compiled remote debug support in to the kernel, added kernel 
command line parameters and tried a dozen different configurations... but 
never got a "Wait for gdb client connection..." message at boot time. The box 
happily continues to boot on. On the other hand, there seems to be support 
for debugging in the kernel source since there is a .../dbg_io.c 
implementation.

I guess I am not really sure what to do with it at this point... I read 
documentation and mailing list archives... no joy!

If anyone on this list would have some pointers and/or suggestions I'd greatly 
appreciate that :-)!!!

Thanks a lot,

Patrick

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From: Jun Sun <[email-masked]>
Date: Fri, 27 Jun 2003 14:19:45 -0700

> for debugging in the kernel source since there is a .../dbg_io.c 

Kgdb support is board dependent.  Some boards, such as Malta, decide to
skip kgdb _even when_ you configure it.  To activate kgdb, you need to
pass command line args, such as "kgdb=ttyS1", to kernel.  What a smart idea. :)

Check the source for your board.

What I like to see is kgdb should be activated when it is configured.
However, "nokgdb" argument can be passed to kernel to skip it even when
kgdb is configured.

Jun

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From: [email-masked] (Patrick Hilt)
Date: Fri, 27 Jun 2003 15:18:32 -0400

Hi Jun!
Thank you very much for your reply! I very much appreciate it! I think I am 
getting a little confused now... I read your "Linux MIPS porting howto" (very 
informative, thanks a lot :-) and consulted some other documents about this 
and there it says to have a kernel command line such as "... gdb gdbttys=1 
gdbbaud=115200". Now, should I just try to add "kgdb=ttys1" to that or 
replace the previous command with it. Sorry if I am asking a stupid question 
but this process is not very well documented... somehow...

Again, thanks a lot for your help!!

Patrick

On Friday 27 June 2003 05:19 pm, Jun Sun wrote:
> > I just recently started working on Broadcom MIPS32 architecture (7115
> > chipset based STB, Broadcom modified 2.4.18 kernel) and have been trying
> > to get kgdb setup to do some kernel source level debugging... with little
> > success I might add ;-|. I compiled remote debug support in to the
> > kernel, added kernel command line parameters and tried a dozen different
> > configurations... but never got a "Wait for gdb client connection..."
> > message at boot time.  The box happily continues to boot on. On the other
> > hand, there seems to be support for debugging in the kernel source since
> > there is a .../dbg_io.c implementation.
>

---

From: Jun Sun <[email-masked]>
Date: Fri, 27 Jun 2003 15:45:47 -0700

> but this process is not very well documented... somehow...

The exact command can only be found in the kernel tree for that board.
Since we don't have the source code for your board, you have
to figure it out yourself.

For example, the way to figure what command Malta wants for kgdb
is to look at arch/mips/mips-boards/malta/malta_setup.c.

Jun