Mark Lord wrote:

hdparm works for some SCSI devices already, and support for
more is already on the way.  I imagine I can have it handle
whatever new ioctls() are being provided from libata as well.

Care to point me at them?

No new ioctls :)  Say no to ioctls :)

libata _may_ support HDIO_DRIVE_CMD, but more likely will support 
http://www.t10.org/ftp/t10/document.04/04-262r1.pdf

and simply use existing interfaces.

	Jeff