Thank you Nick, please see below.
On Sun, Nov 30, 2025 at 08:45:07PM -0500, Nick Holland wrote:
> On 11/30/25 5:00 AM, Avon Robertson wrote:
> > My home router hangs while booting /bsd.sp at the following line:
> >
> > root on sd0a (cd6f434607620efd.a) swap on sd0b dump on sd0b
> >
> > The router does not hang while booting if:
> >
> > > boot hd0a:/bsd.sp -c
> > and then
> > disable amdgpu
> > is specified in UKC followed by
> > quit
> >
> > However; as
> >
> > $ cat /etc/bsd.re-config
> > disable amdgpu
> >
> > has been as above for 10 weeks and during that time /bsd has booted
> > daily without errors occurring, my question is:
> >
> > what am I misunderstanding in the bsd.re-config(5) description below?
> >
> > DESCRIPTION
> > The bsd.re-config file contains kernel modification commands in
> > config(8) format. If present, it is used during system startup to
> > configure the kernel that will be running at the next boot. It can
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > be used to enable or disable specific devices in the kernel.
> >
> > The router was sysupgrade'd -s this morning to:
> >
> > OpenBSD 7.8-current (GENERIC.MP) #127: Sat Nov 29 10:44:59 MST 2025
> > [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
> >
> > OpenBSD 7.8-current (GENERIC) #126: Sat Nov 29 10:32:29 MST 2025
> > [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC
> >
> > TIA for your input.
> >
>
> I do believe you understand the words a bit differently than intended.
>
> Remember: OpenBSD relinks the kernel every boot. Sequence of events:
> 1) boot a kernel
> 2) kernel is running, multi-user, and in control of the hardware.
> 3) System startup takes place ... including
> 3a) daemons
> 3...)
> 3k) /bsd is relinked (KARL -- Kernel Address Randomization Link)
> 3...)
> 4) System is fully on-line and devoted to your tasks
> 5) ...time goes by, you do stuff...
> 6) you reboot
> 1) boot a kernel (relinked in step 3a above)
>
> Now read the description again...
> "If present, it is used during system startup [step 3!!] to configure the
> kernel that will be running at the next boot [step 6 and later]"
>
> So... your file impacts the NEXT /bsd that will boot...not the one
> you happen to tell it to boot at the boot> prompt.
> I suspect you (and I, initially) took "system startup" to mean "kernel
> loading" -- no, kernel config is done during relinking, NOT during load,
> and is part of the operation AFTER the system is multi-user, but not
> before you can say it is finished starting.
>
> BUT -- you aren't booting /bsd -- you override and booted /bsd.sp --
> which a simple "ls -l /bsd*" will show you has NOT been modified:
>
> $ ls -l /bsd*
> -rwx------ 1 root wheel 32283298 Nov 22 01:03 /bsd*
> -rwx------ 1 root wheel 32271586 Nov 21 23:42 /bsd.booted*
> -rw------- 1 root wheel 4804509 Oct 13 08:07 /bsd.rd
> -rwx------ 1 root wheel 32162643 Oct 13 08:07 /bsd.sp*
> $ uptime
> 8:26PM up 8 days, 20:23, 3 users, load averages: 0.00, 0.01, 0.00
>
>
> Though keep in mind, sometimes my role in life is to provide a wrong
> answer so the smart people will have an opportunity to jump up and
> down and point out how stupid I am, and provide the right answer. :)
>
I suspect next paragraph was part of another email, so I will disregard
it.
> As for your actual problem -- SOME video systems really don't like to
> boot or run if a monitor is not attached. There are "cheater plugs"
> ("HDMI Dummy Plugs") made that will plug into an HDMI port and
> convince the GPU a monitor is attached. Apparently, they are often
> used in cryptomining, maybe AI, using GPUs as processors rather than
> displays. Pretty cheap, under $10ea. I've got a few machines that
> need these to do sysupdates, bsd.rd will not work without an attached
> monitor, the full kernels will.
>
> Nick.
>
I will read again (and again) what you have written about what happens.
$ doas /sbin/halt -p # To halt a running /bsd
Consider your 1):
I cold boot. I reach the '>boot ' prompt (thanks to biosboot(8).
boot(8)'s main purpose is to load the system kernel, which I do e.g.:
boot> hd0a:/bsd.sp # Now I need to convince myself why /bsd.sp
# does/should not honour the contents of
# /etc/bsd.re-config because it used to.
Again, thank you for your comments Nick.
--
aer
