shutdown -r not rebooting

[Thomas Klausner <tk%giga.or.at@localhost>]

Since a couple of weeks (I'm not sure exactly when), 'shutdown -r now'
doesn't reboot any longer for me.

It writes the usual detach messages but then stops with
atabus12: detached
rebootin

and that's it.

Has anyone else seen this?

I noted that my dmesg output now contains a newer ACPI version than
before, could something have happened with that import that causes
this?
 Thomas