Saturday, July 21, 2018

Fedora Kernel (well 4.17 kernel) issue resolvable

I've been using a Thinkpad p50 for work since I joined Red Hat. And I'm running Fedora on it instead of Red Hat Enterprise Linux workstation so that I can be more current.

However, that bit me recently when I upgraded to Fedora 28. The built-in Intel dual-band AC 8260 (rev 3a) failed to work on the newer 4.17 kernel. This led me down some dark roads as I switched to an rc 4.18 kernel which had even more problems (though that kernel did have working iwlwifi.)

A productive Saturday morning, led me to patch and test my 4.17 Fedora 28 kernel successfully. The short version is you need to revert one change in the kernel as detailed here:
https://lkml.org/lkml/2018/7/1/104

and then build Fedora kernel rpms (which I haven't done in more than a decade and a lot has changed in that decade). See:
https://fedoraproject.org/wiki/Building_a_custom_kernel

and it has one thing out of date as well. The command:
# sudo /usr/libexec/pesign/pesign-authorize-user

should be just:
# sudo /usr/libexec/pesign/pesign-authorize
A Fedora rpm kernel build gives you time to mow the yard, bike to Starbucks, etc. So don't expect it to finish in minutes. Use the scale of hours.

PS. In linkifying this post, I see that 4.17 COULD HAVE BEEN A CONTENDER for Linux kernel 5.0. That would have scared me enough to hold off... oh well. YMMV. Enjoy.