ALT_BREAK_TO... + ILO ... missing something in config ...

Danny Braniss danny at
Sat Mar 28 01:36:54 PDT 2009

> Due to an issue I'm having with 7.x, and trying to track it down, I spent 
> tonight getting my server setup to allow my to break into the debugger 
> when it hangs, and hopefully dump core ...
> But, although I *think* I've got it all, I'm obviously missing something, 
> as it isn't breaking ...
> First ... I'm running a proliant server, and when I connect via SSH to ILO 
> on that machine, and type 'vsp', I get a shell as I expect, I can type, 
> etc ... when I reboot the machine, I get the opening splash screen with 
> the 7(?) options (normal boot, single user mode, etc, etc) ... but I get 
> nothing between that and the login prompt ... first sign of a problem, 
> maybe?

not realy, you at least have confirmation that you are talking
correctly via the serial port. Till this point boot is using
the BIOS routines to talk via the serial port. Later, the kernel
tries to use it's routines/knowledge of the serial port.

> Next, the easy question ... what is the key stroke to issue when one has 
> ALT_BREAK_TO_DEBUGGER is set in the kernel? I thought it was CR ~ ^b ... 
> is that correct?  I'm using putty to connect via ssh, if that makes a 
> difference ... I've also tried using the browser interface into ilo / vsp, 
> same lack of a result ...

unless the serial port is setup as console, check if /boot/device.hints
escaping to the debugger is not caught.
btw, Jeremy Chadwick had a nice explanation, but I lost the URL.

> Beyond adding sio device driver to my kernel, I've also got:
> options         ALT_BREAK_TO_DEBUGGER
> options         KDB
> options         DDB
> Missing a kernel option maybe?
> I have the following in /boot/loader.conf:
> comconsole_speed="9600"
> console="vidconsole,comconsole" # A comma separated list of console(s)
> boot_multicons="-D" # -D: Use multiple consoles
> boot_serial="-h" # -h: Use serial console
> So ... eithe rI don't have it enabled like I think, or I'm doing the wrong 
> key stroke ... or ...
> Thx

you are very close!, but each hardware/bios needs a different solution :-(


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