Comment 11 for bug 795239

The problem for me seems to be caused by /etc/udev/rules.d/70-persistent-cd.rules containing two entries for the same optical drive after upgrading to 12.10 from 12.04:

# HL-DT-ST_DVD+_-RW_GU10N (pci-0000:00:1f.2-scsi-1:0:0:0)
SUBSYSTEM=="block", ENV{ID_CDROM}=="?*", ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-1:0:0:0", SYMLINK+="cdrom", ENV{GENERATED}="1"
SUBSYSTEM=="block", ENV{ID_CDROM}=="?*", ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-1:0:0:0", SYMLINK+="cdrw", ENV{GENERATED}="1"
SUBSYSTEM=="block", ENV{ID_CDROM}=="?*", ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-1:0:0:0", SYMLINK+="dvd", ENV{GENERATED}="1"
SUBSYSTEM=="block", ENV{ID_CDROM}=="?*", ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-1:0:0:0", SYMLINK+="dvdrw", ENV{GENERATED}="1"

# HL-DT-ST_DVD+_-RW_GU10N (pci-0000:00:1f.2-scsi-0:0:0:0)
SUBSYSTEM=="block", ENV{ID_CDROM}=="?*", ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-0:0:0:0", SYMLINK+="cdrom1", ENV{GENERATED}="1"
SUBSYSTEM=="block", ENV{ID_CDROM}=="?*", ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-0:0:0:0", SYMLINK+="cdrw1", ENV{GENERATED}="1"
SUBSYSTEM=="block", ENV{ID_CDROM}=="?*", ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-0:0:0:0", SYMLINK+="dvd1", ENV{GENERATED}="1"
SUBSYSTEM=="block", ENV{ID_CDROM}=="?*", ENV{ID_PATH}=="pci-0000:00:1f.2-scsi-0:0:0:0", SYMLINK+="dvdrw1", ENV{GENERATED}="1"

The last one is in effect (giving device aliases for the only optical drive in my laptop a numeric suffix of "1" instead of none). Since the file is generated, I just deleted it and rebooted. Now there is only one entry, proper device links and eject works again. (Looks like the only difference between the entries is SCSI device numbering, "scsi-1:0:0:0" vs "scsi-0:0:0:0" in Ubuntu 12.10.)