Interestingly, EXACTLY the same thing happened to me. I actually bought a vanilla IDE controller for a spare disk, and in what showed up the documentation claimed it was a DM-8401R, but lspci shows what you see: and IT8212.
The answer was to get the good stuff from here:
http://www.iteusa.com/productInfo/Download.html#IT8212%20ATA133%20Controller
The driver install was a doddle (well documented, and easy to apply Mandrake 9.1 instructions to 9.2). For heavens sake: these guys even provide the specs online. And the driver seems to work, though I am not stressing it.