Comment 4 for bug 85085

After doing some intensiv search through the web, I found out that its not possible to create a dm device for the CD/DVD drive which cryptsetup needs.

echo 0 $(blockdev --getsize /dev/hdc) linear /dev/hdc 0 | dmsetup create hdc

This command fails with the following error message:

device-mapper: table: 254:5: linear: dm-linear: Device lookup failed
device-mapper: ioctl: error adding target to table

What works is, creating a loop device with /dev/hdc and mount the loopdevice with cryptsetup. But this does not work with the automatic cryptpassword dialog.