F17 luks weirdness

[Bruno Wolff III]

On Wed, May 23, 2012 at 14:09:59 -0400,
   Peter A <loony at loonybin.org> wrote:
>All,
>
>I'm having an issue with encrypted disk setup on my Dell M6600 
>laptop. During boot of Fedora 17 (originally installed from alpha, 
>yum updated current ever since), I get prompted for the password but 
>the device shown in the prompt changes. If it ends up picking md127p1 
>the boot device is not decrypted the devices but instead fails with a 
>luks error trying to access the device. If I get prompted for the 
>pass phrase for any other device, boot up is successful, including 
>mounting the md127p1 partition.

I would take a look at /etc/crypttab and make sure it appears to be correct. 
You can use blkid to get uuids and make sure they match up properly. 
If you change /etc/crypttab, you'll want to rerun dracut so that a good 
copy ends up in the initramfs file.