There doesn't seem to be a list for MI device driver issues, so I picked
this one as the closest that might do for this query (a list for device
driver issues might be a good idea).

Can someone tell me how I test whether the quirk SDEV_NOLUNS is necessary
for a CD player or not?

I have a TEAC 32x, for which the quirk would be, if it is needed ...

        {{T_CDROM, T_REMOV,
         "TEAC    ", "CD-532S   10A1EH", "1.0A"}, SDEV_NOLUNS},

but I'm not sure if it is, or isn't.   It seems (without a lot of
testing) to work OK without it, but the quirk table has a couple of
other TEAC drives listed (with quite similar ident strings) that do
have the quirk.

What is likely to fail if this quirk is needed, but not defined for
the drive?

If it turns out to be necessary I'll submit a PR for it, but I don't
want to do that based merely upon "that drive needs this, so this one
must too" type analysis.

kre

ps: if it matters, it is connected to an alpha (PC164) via a qlogic 1020.
Also, if the quirk is connected to audio performance in some way, then I'll
probably never find out.