IPMI serial console

[Daniel O'Connor]

On 22/02/2013, at 12:02, Jeremy Chadwick <jdc at koitsu.org> wrote:
>> Hmm I tried putting '-S 115200' in /boot.config and it broke - the boot process didn't run the loader (or kernel).
> 
> I'll talk a bit about this -- again, sorry for the verbosity.  I'll
> explain what I've historically used/done, then speculate a bit about
> your IPMI stuff:
> 
> For me, on systems without IPMI, all I had to do was this (and nothing
> else):
> 
> * Put the following in /boot.config:
> 
> -S115200 -Dh

This breaks the boot for me, boot.config has to contain more than just flags it seems. In any case I believe setting boot_multicons and boot_serial is the same as -Dh. Not sure about the baud rate though.

<snip>
>  situation may be different because you have 3 serial ports (2
> classic DB9 ports or headers, and one "fake" via IPMI), so you may need
> to rely entirely on /boot/loader.conf to accomplish use of the IPMI one,
> unless you wanted to set BOOT_COMCONSOLE_PORT.

OK, I made some more progress, I rebuilt the /usr/src/sys/boot with BOOT_COMCONSOLE_SPEED=115200  BOOT_COMCONSOLE_PORT=0x3e8 and now the loader talks to me without VGA to serial redirection.

> Possibly the reason you see via the IPMI serial port at this stage is
> because IPMI also does VGA-to-IPMI output, so what you're seeing on the
> IPMI serial port is actually from the VGA console (speculation on my
> part).

Yes this was the case until just now.

> Debugging all of this is as you know a PITA because of where during the
> whole startup process it lies.  IPMI just makes this whole thing an even
> bigger mess because it ties itself in to bits/pieces along the way,
> which a kernel (or even a bootloader, depending on what it touches and
> how), can mess up.  This is why I've always stuck with the classic DB9
> serial ports on the backplane; I know how to get FreeBSD to behave right
> with those, everything else is voodoo.  :-)

Yep, it's all kludges bolted on top of hacks.

> Part of me wonders if it's possible to disable, say, COM1 in the BIOS,
> then in the IPMI firmware tell it to user a serial I/O port of 0x3f8,
> IRQ 4 (i.e. COM1) and see if that works with the method I describe
> above.  I don't have much familiarity with IPMI by choice, solely
> because of situations exactly like what you're going through.  I have
> the same opinion of those damn NIC ASF things (see bge(4)) -- which is

Yeah I may look at that if I can't proceed any further.

> exactly why many motherboard vendors that do IPMI now offer a
> *physically separate NIC/RJ45 port* for it, rather than "piggybacking":
> the latter caused so much pain/anger that it wasn't worth it.

I assumed that the separate NIC was to avoid this problem, however I have since found that the default on the SM boards I looked at is to use the dedicated port otherwise share(!). So the worst of both worlds, hooray!

--
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
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