Some information,
here. The relevant piece of info is:
Quote:
Most players (eg mplayer/vlc) with most DVD drives are able to ignore the value of the region setting. However, it must have been set to something; if it hasn't been initialized, even non-region-restricted DVDs won't play.
|
but it's not clear who or what changed the region settings, most likely the player itself through the regionset command. Anyway, you can use regionset to check the current setting of the DVD drive and pay attention to the limit of changes, after which the region setting will be stuck on the last used.