AHCI and ZFS: root mount error

[Romain Garbage]

Hello,

After setting ahci_load="YES" in /boot/loader.conf, I get a root mount error.
ahci seems to attach to disk correctly (I get ada0 messages with no error)

Without ahci_load="YES", system boots fine, with ata module attaching to disk.

I have a full zfs system, set up following wiki instructions:
http://wiki.freebsd.org/RootOnZFS/ZFSBootPartition
(MBR scheme, ZFS in a FreeBSD slice, together with a swap partition)

I'm using a GENERIC kernel, RELENG_8 branch.

My /boot/loader.conf:
zfs_load="YES"
vfs.root.mountfrom="zfs:zroot"
nvidia_load="YES"
snd_hda_load="YES"
tmpfs_load="YES"
coretemp_load="YES"

Regards,
Romain