I did manage to figure this out. I have to give a shout out to the Arch Linux people for doing an excellent job on their documentation. I frequently find things in there that help with my systems (all Fedora or Raspbian) even though I don't actually run Arch except in a VM for playing around and learning. I found their suspend and hibernate page at https://wiki.archlinux.org/index.php/Power_management/Suspend_and_hibernate to be very helpful. Arch uses something called "mkcpio" rather than "dracut" that Fedora uses, but the main thing it mentions is the need to rebuild the initramfs image to include the "resume" module. That works! And my Dell desktop will now hibernate. The command was just "dracut --add resume" (I first saved a copy of the current img file just in case). I find it interesting that I have been using hibernation on Fedora for years and never had to explicitly do this. I just checked my main Fedora server, and "lsinitrd" shows that there is no "resume" module in the initramfs file. But I have never tried hibernating the server. My laptop *does* have the resume module even though I never explicitly included it. There is nothing I can find in /etc/dracut that specifies that the resume module should be included, but it is there. There is still a lot about how all this works that I don't understand.

And to my embarrassment, I found a previous reference on this list to using dracut to add the resume module for hibernation, but it did not come up in my previous searches of my archived list messages. In there it is suggested that perhaps the resume module was only added in by default if you create a swap partition at install time, but I always do that so I'm not quite sure what happened this time.

I don't use Secure Boot on my desktop or my servers because it makes too many things a lot more painful (like third-party drivers such as nvidia) and since these systems never leave my house, the security risk is minimal. 

--Greg