[elrepo] Building for a non-standard kernel

[Roger Sewell]

If this is not the right place to post this query please tell me where
is.

I have been sent a built test kernel with a bug fixed, based on a kernel
many releases later than the current 8.3 RHEL kernel, along with
corresponding versions of the associated devel packages. 

1. Where can I find instructions for how to rebuild the
   kmod-megaraid_sas RPM for this non-standard kernel from the 8.3 SRPM
   package which I have ? (I tried just changing the definition of
   kmod_kernel_version to 4.18.0-287.el8.test, and it appeared to build
   OK apart from some warnings of whose severity I'm uncertain, it
   installed fine, but booting the resulting kernel produced apparently
   correct boot.log and messages content, but unusable video output both
   on GDM and the tty interfaces.)

2. Is it indeed possible to build it for an installed kernel that is not
   the running kernel ? (If not, then I cannot rebuild on my existing
   hardware.) 

Thank you.