On 2013-08-23 17:43, Stuart Henderson wrote:
> On 2013-08-23, Hugo Osvaldo Barrera <h...@osvaldobarrera.com.ar> wrote:
> > Hi!
> > I've started managing a serial server through a serial console, and have
> > come into some unusual issues.
> > I followed the instrucitons on faq 7.7, and also configured by BIOS
> > accordingly.
> >
> > When I conect my PC to the server, I see BIOS and POST output properly,
> > I then see the OpenBSD bootloader properly, and all the kernel messages
come
> > out fine (ie: the white-on-blue text), however, AFTER the kernel
messages,
> > I only see the following sixteen characters and nothing else (though
> > later kernel messages like plugging in a USB are shown properly).
> >
> > In single user mode, this would be:
> > "Enter pathname o"
> >
> > In non-single user mode, this would be
> > "Automatic boot i"
> >
> > It's extremely odd. I'm cleary not having cable issues, wrong rates,
> > or anything alike, because I'm seeing kernel output just fine.
>
> This is exactly what you would see if the IRQ assignment is wrong.
> There are other possibilities too, but this is easy to check in the
> BIOS, and is a somewhat likely problem.
>
> The first port (known as com0 in OpenBSD, com1 in MSDOS) should be at
> 0x3f8 irq 4, the second should be 0x2f8 irq 3. Sometimes vendors
> (I've seen it with Jetway) have been known to screw up and reverse
> the irq assignments.
Ah, thanks! I had checked that 0x3f8 was being used, but the irqs were
mixed up (ie: they were swapped).
Oddly I'm not seeing the first bit of the bootloader any more ("Using
drive 0, partition 3..."), but I *am* seeing the important part which
is the prompt for a boot commands.
I'm curious though; why were kernel outputs being outputted
properly? Shouldn't those have failed to display as well?
>
> Some other OS take these from ISAPNP but OpenBSD hardcodes the
> standard values for a PC-compatible machine and expects the port to
> be there.
Why doesn't OpenBSD attempt to do this as well? Is there some reason to
avoid that, or is it simply because nobody's gotten around to it?
>
> > com0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
> > com0: console
> > com1 at isa0 port 0x2f8/8 irq 3: ns16550a, 16 byte fifo
>
The rebooting issue is now gone too. I had assumed they were related,
and they are.
Thanks,
--
Hugo Osvaldo Barrera
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