Strange DVD Drive Behavior

[Daniel Fussell]

I bought 2 surplus HP dc7700's with LG DVD burners that are acting kind 
of funny.  They will read CDs and data DVDs no problem, but not (most) 
commercial DVD-Video discs.  It complains that there is no media found 
if I try to dd from it, vlc says (via the libdvdread/libdvdcss2 
libraries) that it can't open the device.  It does this in Windows XP as 
far as I can tell, as well as each of the Debian squeeze/wheezy/sid 
releases and every version of libdvdcss2 I tried from debian-multimedia, 
and every debian kernel package  since 2.6.32.  So I don't think it's a 
driver issue.  There aren't any firmware updates for the drive that HP 
has published, and LG has deferred any such update to the OEM.

Some internet forums suggest that the DVD laser is burned out, but that 
doesn't explain why it has no problem with a data DVD (assuming it has 2 
separate lasers), and I've even (while partly dissassembled) gotten it 
to read a DVD-Video home movie I made with Cinelerra and DeVeDe (burned 
from a different machine of course).

The really funny thing was, when I ejected that home movie, a warning 
was displayed in Gnome3 to leave the disk in the drive while it finished 
writing to the disk, though I had only been using it with VLC and Xine, 
and I thought writing an ISO would finalize the disk.  I'm a KDE user, 
so I don't know if this is normal or not, nor what it might be writing 
(access logs?  MPAA spyware/trackers?  "HP wuz here"?).

I thought it might be a DVD region code problem, but the correct code is 
displayed in Windows.  When I use regionset to see if resetting it will 
resolve the issue, it says it can't open the device.

Yes, I'm a member of the cdrom group, but I have problems even when 
trying things as root.

I'm starting to wonder if there is a DVD-Video enable DRM signal that 
the bios or windows driver is supposed to send to keep all those open 
source linux pirates from watching videos on purchased media, rather 
than getting it from bit torrent like everyone else.  Or if the this is 
supposed to be an MPEG licensing scheme for enforcing periodic payments 
for DVD codecs by disabling DVD-Video support at a predefined 
obsolescence date, requiring a replacement purchase.  I have a third 
(much older) LG drive that as far as I can tell stopped working with 
DVDs out of the blue one day as well (though I didn't have data DVDs to 
test with at the time).

Or am I totally forgetting some obvious -enable-dvd-video kernel 
parameter that I've long since forgotten about?

Grazie,
;-Daniel Fussell