AHCI driver progress report - hot-swap PM and parallel probe!

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

    The hot-swap Port Multiplier support should now be quite solid.
    I fixed numerous issues with device signature probing and other
    things and so far I can pop in and pop out drives either direct-attached
    or in a PM enclosure without freaking the driver out.

    In addition to probing the SATA ports more quickly, the AHCI driver
    now also probes *ALL* of the physical SATA ports in parallel.  Needless
    to say, this really improves attach times during boot.  If you have
    multiple PM (port multiplier) enclosures (not that I think anyone does),
    but if you do, the individual targets in the enclosure have to be
    probed sequentially, but all the enclosures will be probed in parallel.

    --

    I would like to stick the AHCI driver into GENERIC and go with it for
    the release.  The only sticking point is that people who update and who
    have AHCI devices will have to rename their disks in /etc/fstab and
    /etc/rc.conf (and maybe even /boot/loader.conf if you use a BOOT+HAMMER
    setup).

						-Matt