The modules are not necessarily the same: "libahci" was introduced in
commit 365cfa1ed5a36f9bcb9f64c9f0f52155af2e9fef
Author: Anton Vorontsov <avorontsov@ru.mvista.com>
Date: Sun Mar 28 00:22:14 2010 -0400
ahci: Move generic code into libahci
so there exists the possibility that the initramfs builder, or whatever
is being used to load your ATA drivers, missed this dependency. Modern
initramfs builders should be able to figure out module dependencies, so
this /shouldn't/ be an issue... but it might be.
Jeff
--