[Bug 235944] jedec_dimm(4) does not attach to KFA2 (aka Galax) Hall of Fame DDR4 sticks

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=235944

--- Comment #17 from Ravi Pokala <rpokala at panasas.com> ---
(In reply to Andriy Gapon from comment #15)

> also, I think that it is wrong to fail the attach on a failure to access TSOD.
> Many DDR3 DIMMs simply do not have it (not sure about DDR4).
> I think that all "server" RDIMMS/LRDIMMs and consumer ECC-capable UDIMMS that I've seen had it.  But all non-ECC UDIMMs didn't.
> So, a missing TSOD should not be a fatal error.

Agreed, which is why it isn't:

================================================================
        /* The MSBit of the TSOD-presence byte reports whether or not the TSOD
         * is in fact present. If it is, read manufacturer and device info from
         * it to confirm that it's a valid TSOD device. It's an error if any of
         * those bytes are unreadable; it's not an error if the device is
simply
         * not known to us (tsod_match == NULL).
         * While DDR3 and DDR4 don't explicitly require a TSOD, essentially all
         * DDR3 and DDR4 DIMMs include one.
         */
        rc = smbus_readb(sc->smbus, sc->spd_addr, tsod_present_offset, &byte);
...
        if (byte & 0x80) {
                tsod_present = true;
...
        } else {
                tsod_match = NULL;
                tsod_present = false;
        }
...
        /* Create the temperature sysctl IFF the TSOD is present and valid */
        if (tsod_present && (tsod_match != NULL)) {
================================================================

-- 
You are receiving this mail because:
You are the assignee for the bug.