ECC support

[Chris H]

On Tue, 15 Sep 2015 13:53:27 -0700 Dieter BSD <dieterbsd at gmail.com> wrote

> Many of AMD's CPU/APU parts support ECC memory.  Not just the top of the
> line parts, but also many of the less expensive, less power hungry parts.
> However, many (most?) of the boards for these chips do not support ECC,
> or at least do not admit to it.  They specify "non-ECC memory".
> 
> Obviously there have to be connections between the memory controller and
> the memory for the extra bits.  Aside from a little extra time for the
> board designer to add a few traces to the wire list, this would not
> raise the cost of the board.  Despite this I have read that some boards
> lack the necessary traces.
> 
> Does the firmware have to do anything to support ECC?  Program a few
> registers in the memory controller perhaps?  A few boards have FLOSS
> firmware available, so this code could be added, but most boards do not
> have firmware sources available.
> 
> Assuming that a board does have the necessary connections but
> the firmware does not have ECC support, is there some reason that
> ECC support could not be added to the OS instead of the firmware?
> I grepped through FreeBSD 8.2 and 10.1 sources but couldn't find
> anything that looked relevant.  Also did not find any code that
> reported ECC errors, other than one device.  Perhaps I missed it?
> 
> I've been running machines with ECC for 15-20 years and have never seen
> a report of an ECC error from either NetBSD or FreeBSD.  I have seen
> reports of ECC errors from Digital Unix.  And remember getting panics
> due to parity errors on machines before ECC.  So I'm thinking that
> the BSDs must ignore hardware reports of single bit ECC errors.  :-(
Oh. You mean like the one I got about an hour before you sent
this?

MCA: Bank 1, Status 0x9400000000000151
MCA: Global Cap 0x0000000000000106, Status 0x0000000000000000
MCA: Vendor "AuthenticAMD", ID 0x100f52, APIC ID 2

MCA: Address 0x81cc0e9f0

Kind of freaky. I've never had this error on this board before.
On others tho.

Try a search for MCA instead.

HTH

--Chris


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