Comment # 25 on bug 909418 from Oliver Neukum

If I remove the "--lock-media" option I get a strange result. The button works
again on unmounted media. But there's no event. With a mounted medium the
button doesn't eject the CD, yet an event is generated. It seems like this
interface is flawed, if you want consistent notification about events for a
GUI.


linux-0dmf:/usr/lib/udev/rules.d # udevadm monitor -k -p
monitor will print the received events for:
KERNEL - the kernel uevent

KERNEL[34242.269050] change  
/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sr0
(block)
ACTION=change
DEVNAME=/dev/sr0
DEVPATH=/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sr0
DEVTYPE=disk
DISK_MEDIA_CHANGE=1
MAJOR=11
MINOR=0
SEQNUM=4252
SUBSYSTEM=block

KERNEL[34272.733186] change  
/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sr0
(block)
ACTION=change
DEVNAME=/dev/sr0
DEVPATH=/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sr0
DEVTYPE=disk
DISK_MEDIA_CHANGE=1
MAJOR=11
MINOR=0
SEQNUM=4253
SUBSYSTEM=block

^Clinux-0dmf:/usr/lib/udev/rules.d # mount /dev/sr0 /mnt
mount: /dev/sr0 is write-protected, mounting read-only
linux-0dmf:/usr/lib/udev/rules.d # udevadm monitor -k -p
monitor will print the received events for:
KERNEL - the kernel uevent

KERNEL[34312.669165] change  
/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sr0
(block)                                                                         
ACTION=change                                                                  
                                                                               
                                                                
DEVNAME=/dev/sr0                                                                
DEVPATH=/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sr0 
DEVTYPE=disk                                                                    
DISK_EJECT_REQUEST=1                                                            
MAJOR=11                                                                        
MINOR=0                                                                         
SEQNUM=4255                                                                     
SUBSYSTEM=block