ahci: attachment to atapi device

[Matthew Dillon]

    I've got some of it figured out.  I loaded up Virtual Box on my windows
    box.

    I figured out part of the interrupt issue.  VB and the Intel ICH
    chipsets do not have Async Notification.  Because of that I wasn't
    setting an interrupt bit called SDBE which is apparently used by the
    Intel chipset to notify when a NCQ command completes.

    That explains why it got past the probe and then timed-out trying
    to read from the disk.

    I'm working on some other issues related to VBOX, then I'll commit the
    whole mess and people can try the driver again.  I hope to commit
    this evening.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>