FreeBSD vs Region Code DVDs

[Scott Long]

Sean C. Farley wrote:
> On Thu, 3 May 2007, Ulrich Spoerlein wrote:
> 
>> Hi all,
>>
>> I'm having a hard time getting my external (USB, Firewire) Plextor
>> PX-755UF to read any retail DVDs at all. I can read any kind of CDs
>> and also DVD-Rs. But mastered DVDs are invisible to FreeBSD.
>>
>> I can not even read a single sector from such a DVD with the external
>> drive, but it's working just fine with the internal one. It's really
>> driving me nuts.
> 
> <snip>
> 
>> The NEC drive can read DVDs just fine (although it sucks).
>>
>> % recoverdisk /dev/cd1
>>        start    size           len state          done     
>> remaining    % done
>>            0 1048576    7411912704     0             0    7411912704 
>> 0.0000000^C
>> (130)% recoverdisk /dev/cd0
>> recoverdisk: DIOCGMEDIASIZE failed: No such file or directory
>> (1)% dd if=/dev/cd0 bs=2048
>> 0+0 records in
>> 0+0 records out
>> 0 bytes transferred in 0.000093 secs (0 bytes/sec)
>>
>> If I attach the device via Firewire, it's just the same. Perhaps it
>> requires some sort of quirk? Where should I start looking for debug
>> output? Which test should I run. Any help would be greatly
>> appreciated.
> 
> I had an issue with ripping some DVD's to my laptop before a trip I made
> (note:  no distribution occurred (for the lawyers :))).  I wanted to
> just use dd to do it, but dd would fail after a small amount of data was
> read.  If I first played a little of the DVD with mplayer, then dd would
> work afterwards.  It probably had something to do with mplayer
> whispering sweet nothings to the DVD player.
> 
> Sean

Yes, there are ioctls that wind up instructing DVD players to be happy.
Once they are issued, they remain in effect until the disk is changed or
the device is reset.  An argument could be made that every open of a DVD
device should perform this magic, and not rely on the app to do it.  But
an argument could also be made to leave well enough alone =-)

Scott