A common cause of this behavior is device polling by deamons like hald and udevd. You can temporarily disable polling by hald and udev to see if these may be the cause in your case.
If you are running hald:
hal-disable-polling --device /dev/dvd
Note your DVD drive may not be symlinked /dev/dvd, it could be /dev/sr0, /dev/dvd0, etc. If you get an error like "Cannot find storage device /dev/dvd", you can try one of the other device names.
Now temporarily stop polling by udev with this:
udisks --inhibit-polling /dev/dvd
(this command will appear to hang - it is disabling polling until you hit
If this stops your device from frequently spinning, see my notes below about making the udev rule changes.
If disabling hald and udisks polling makes no difference, then you can re-enable hald control of the device with this:
hal-disable-polling --enable-polling --device /dev/dvd
Disabling polling of your DVD device may have the side effect of requiring you to mount optical media manually. Your drive may continue to provide notification to udev that it should take some action upon media insertion.
Making udisks ignore your optical device is a simple rule. I put mine in /etc/udev/rules.d/99-device-polling.rules:
Get your vendor and model strings from the output of
udisks --show-info /dev/dvd. Make the changes active by running
udevadm trigger, then re-examine
udisks --show-info /dev/dvd and note the line "detection by polling:" - it should be 0.