David Hess (davidwhess.delete@this.gmail.com) on March 6, 2021 4:27 am wrote:
> Memory scrubbing is handled by the memory controller and not the operating system, so it has
> to be enabled after the memory is initialized which is easy enough in the BIOS. Caches are
> also scrubbed. Whether errors are reported to the operating system is configurable.

> My workstations have had ECC since the 1990s. Perhaps not coincidentally, they were
> only retired as they became obsolete rather than because of hardware failure.

It's worth remembering that you can have ECC with no firmware support at all if you're willing to accept a window of vulnerability at boot time.

With the AMD memory controllers, you enable ECC after boot with the following sequence:

1. ECC error reporting OFF.


2. Record ECC scrub address (setting to zero optional).


3. ECC scrub rate to maximum.


4. ECC scrubbing ON.


5. Wait for ECC scrub address to wrap around.


6. ECC scrub rate to something reasonable.


7. ECC error reporting ON.