AHCI driver progress report - hot-swap port multiplier support in!

[Matthew Dillon]

    The AHCI driver is progressing very well.  The port multiplier support
    is now much more robust and hot-swap is now fully supported.  I can have
    a few dd's running on some of the drives and pull out and push in the
    remaining (idle) drives while the dd's are running and they don't blow
    up.  And the driver recognizes when drives are removed or inserted.

    I still haven't done major load testing w/ the PM yet and I don't
    consider the PM support to be production ready, but mainly the
    reason is that we need to identify and mount drives by their serial
    number to really be able to make use of a PM enclosure.  The 'daXXX'
    enumeration cannot really be counted on when one has a ton of drives.

    PM performance is still abysmal without FBSS support but that's a
    function of the hardware, not the driver.

    --

    Note these latest changes require a kernel rebuild (quickkernel works)
    as I had to fix some things in CAM.

    --

    There is still a lot of work remaining, including adjusting the locks
    from per-device to per-port and many other things but all the major
    features are now in and working and fairly robust.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>