I've upgraded from Ubuntu 10.10 to LM Maya (With Mate Desktop). On Ubuntu 10.10 I was able to lock DVD hardware button using eject -i 1 (and unlock with eject -i 0), so my drive doesn't accidentally open. After upgrade, this stopped work. I've tried eject -i 1 /dev/sr0, echo 1 > /proc/sys/dev/cdrom/lock and little C program which uses ioctl. Everything failed - I'm still able to open door using HW button.