there are a handful of old ISA-ish drivers that can crash randconfig kernels in various ways. [indefinite lockups, crashes, stomped-over hardware, non-working keyboard, etc.]
I mapped most of them out via many months of trial-and-error - but it would still be nice to have some separate config option to disable the known ones. CONFIG_ALLOW_NON_GENERIC or something like that - which i would unset in the randconfig runs.
( They are not CONFIG_BROKEN per se, because often it's hardware that
cannot be probed in any reliable way - the driver just assumes it's there. )