How to tell whether ECC (memory) is enabled?

John Baldwin jhb at
Fri Nov 5 21:22:15 UTC 2010

On Friday, November 05, 2010 12:09:14 pm Thomas Zander wrote:
> Dear,
> is there any way to inspect a running STABLE machine for the presence
> or state of ECC memory before an MCA "error detected" message actually
> occurs?
> In comparison when I quickly boot the machine in question with a Linux
> live CD, I find (among other EDAC messages) the following output in
> its dmesg:
> ...
> EDAC amd64: ECC is enabled by BIOS, Proceeding with EDAC module initialization
> ...
> During POST, die BIOS also tells me that ECC memory is installed, so
> far so good. But I was a little surprised that the FreeBSD kernel
> tells me absolutely nothing about it. Or do I have to tune loader.conf
> variables?

I think the EDAC register is using the registers for the QPI PCI buses.
There is a driver now to export those PCI buses to the OS in 7.x+.  However,
someone would need to port the EDAC driver (or something similar) to work
with those devices.

John Baldwin

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