Date: Tue, 15 Sep 2015 17:04:32 -0700 From: "Chris H" <bsd-lists@bsdforge.com> To: <freebsd-hackers@freebsd.org> Subject: Re: ECC support Message-ID: <e58306361f7ec1e5a7b85e2b49d865b2@ultimatedns.net> In-Reply-To: <CAA3ZYrBXZn1WpHWYGJYWJDPsk7iDahCas8RhnHC4w%2Babf4w4hA@mail.gmail.com> References: <CAA3ZYrBXZn1WpHWYGJYWJDPsk7iDahCas8RhnHC4w%2Babf4w4hA@mail.gmail.com>
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On Tue, 15 Sep 2015 13:53:27 -0700 Dieter BSD <dieterbsd@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 > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"
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