Hi folks...

I've made some improvements to the USB ZIP driver.  First of all, hot-unplug
works now:

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uhub0 at usb0
uhub0: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 2 ports with 2 removable, self powered
umass0 at uhub0 port 1 configuration 1 interface 0
umass0: Iomega USB Zip 100, rev 1.00/1.00, addr 2, iclass 8/6/80
scsibus0 at umass0: 2 targets, 1 luns per target
sd0 at scsibus0 targ 1 lun 0: <IOMEGA, ZIP 100, 02.U> SCSI0 0/direct removable
sd0: 98304 KB, 96 cyl, 64 head, 32 sec, 512 bytes/sect x 196608 sectors
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uhub0: port error, restarting port 1
umass0: at uhub0 port 1 (addr 2) disconnected
sd0 detached
scsibus0 detached
umass0 detached
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umass0 at uhub0 port 1 configuration 1 interface 0
umass0: Iomega USB Zip 100, rev 1.00/1.00, addr 2, iclass 8/6/80
scsibus0 at umass0: 2 targets, 1 luns per target
sd0 at scsibus0 targ 1 lun 0: <IOMEGA, ZIP 100, 02.U> SCSI0 0/direct removable
sd0: 98304 KB, 96 cyl, 64 head, 32 sec, 512 bytes/sect x 196608 sectors
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Second, I've implemented SCSI sense handling, so that when you swap media,
you won't get an I/O error on the next operation.  This should also make
it possible to detect bad media, etc.

I'm planning on implementing async (not async in the SCSI sense, but rather
interrupt-driven) transfers, and also adding support for non-SCSI and non-Bulk
command sets/transports.  A lot of this work has been done by Nick Himba.

Have fun!

        -- Jason R. Thorpe <thorpej@shagadelic.org>