Currently sys-kernel/dracut have support only for in-kernel suspend but it would be nice if it supported toi as well. Reproducible: Always
You can set TOI to be default suspender and then it doesn't need special support. But OK, I'll enhance it.
Created attachment 316221 [details, diff] 0001-toi-in-progress.patch proof-of-concept. It might not work at all. If anybody is interested in TOI support, please test it and fix it and then it will be applied in the nearest dracut version. I no longer use hibernation, because it is not reliable.
Please reopen if necessary.