Re: Trying to boot a supermicro H8DMT board

On Mon, 17 Jan 2022 15:04:16 +0100
Willem Jan Withagen <wjw@digiware.nl> wrote:

> On 17-1-2022 14:46, Eugene Grosbein wrote:
> > 17.01.2022 20:24, Willem Jan Withagen wrote:
> >
> >>> Well, perform independent hardware (memory) testing with something like memtest86+
> >>> and if it is all right, you show ask someone more knowledgeable. Maybe CC: arch@freebsd.org
> >> Perhaps should have done that when I started, but supplier assured me that
> >> the they just retired the boards with out any issues.
> >> Memtest86 found the faulty DIMM in 30 secs...
> >>
> >> Not sure if we could/want educate vm_mem_init() to actually detect this.
> >> It is still in the part where everthing is still running on the first CPU.
> >> Making things a bit easier to understand what is going on.
> >>
> >> Lets see if the box will run on 3 DIMMs for the rime being.
> >> Then figure out with DMIdecode what we need expand again.
> > Is it ECC memory or non-ECC?
> > The kernel already have full memory testing performed at boot time
> > unless disabled with another loader knob:
> >
> > hw.memtest.tests=0
> >
> > Try booting it with memory testing disabled and without hw.physmem limitation.
> > Maybe it will boot.
> >
> > With ECC, it could be hardware interrupt while kernel runs that test
> > and wrong in-kernel processing of the interrupt.
> 
> Swapped the DIMM with 3 others, but still the same errors.
> Then I changed DIMM slot, and the errors went away.
> So definitely a hardware issue
> 
> when booted FreeBSD reported already only 12Gb in system ( there are 4 
> 4GB dimms)
> Using 8Gb. DIMMs are ECC.
> But then still it would only boot when mem set to 8G.
> 
> Waiting for memtest to finish at least one pass.
> Usually that will take quite some time.
> 
> --WjW
> 
> 

Not sure this is the case, but some motherboards have severe limitation
about DIMM slot usage, if not fully used.

For example, assuming slot No. are B0-0, 1, 2, 3 and B1-0, 1, 2, 3,

 *Must use "interleaved. If 4 in 8 slots are to be used,
  B0-0, B0-2, B1-0, B1-2 shall be used.
  (Some forced B0-1, B0-3, B1-1, B1-3, IIRC)

 *Must NOT use "interleaved.
  B0-0, B0-1, B1-0, B1-1 shall be used.

 *Must NOT use B1 unless B0 is full of DIMs.
  B0-0. B0-1, B0-2, B0-3 shall be used.

and so on, depending on motherboard vendor (at worst, per model.)


-- 
Tomoaki AOKI    <junchoon@dec.sakura.ne.jp>