Kaffeine: Can’t check DMA mode. Permission denied or no such device: “/dev/dvd”

I recently ran into trouble trying to play copy-protected DVDs on my new installation of Kubuntu 8.04 (Hardy Heron beta). Initially it seemed that there was a problem with the installation of libdvdcss2, because Kaffeine kept offering to re-install it. However, after a re-start of Kaffeine from Konsole with wizard mode (kaffeine -w), I got this error :

Can't check DMA mode. Permission denied or no such device: "/dev/dvd"

Odd, considering that Amarok, K9copy and K3B were having absolutely no problems finding and using discs. And there was the clue: in K3B’s configuration screen the drive was identified asscd0. So, I checked from the command line:

me@kubuntu-desktop:~$ ls -l /dev/dvd*
lrwxrwxrwx 1 root root 4 2008-04-14 19:58 /dev/dvd1 -> scd0
lrwxrwxrwx 1 root root 4 2008-04-14 19:58 /dev/dvdrw1 -> scd0

And sure enough, there was no symbolic link between scd0 and /dev/dvd. Simple enough to fix though:

me@kubuntu-desktop:~$ sudo ln -s scd0 /dev/dvd
me@kubuntu-desktop:~$ ls -l /dev/dvd*
lrwxrwxrwx 1 root root 4 2008-04-15 00:03 /dev/dvd -> scd0
lrwxrwxrwx 1 root root 4 2008-04-14 19:58 /dev/dvd1 -> scd0
lrwxrwxrwx 1 root root 4 2008-04-14 19:58 /dev/dvdrw1 -> scd0

All fixed. But for good measure, I checked the cdrom situation. Same issue:

me@kubuntu-desktop:~$ ls -l /dev/cd*
lrwxrwxrwx 1 root root 4 2008-04-14 19:58 /dev/cdrom1 -> scd0
lrwxrwxrwx 1 root root 4 2008-04-14 19:58 /dev/cdrw1 -> scd0

So, for good measure (even though I hadn’t come across any problems):

me@kubuntu-desktop:~$ sudo ln -s scd0 /dev/cdrom
me@kubuntu-desktop:~$ ls -l /dev/cd*
lrwxrwxrwx 1 root root 4 2008-04-15 00:04 /dev/cdrom -> scd0
lrwxrwxrwx 1 root root 4 2008-04-14 19:58 /dev/cdrom1 -> scd0
lrwxrwxrwx 1 root root 4 2008-04-14 19:58 /dev/cdrw1 -> scd0

Now, with all roads leading to Rome, I fired Kaffeine back up again and enjoyed my movie.