o Switch to handling bad SCSI status as a sequencer interrupt
   instead of having the kernel proccess these failures via
   the completion queue.  This is done because:

    - The old scheme required us to pause the sequencer and clear
      critical sections for each SCB.  It seems that these pause
      actions, if coincident with a sequencer FIFO interrupt, would
      result in a FIFO interrupt getting lost or directing to the
      wrong FIFO.  This caused hangs when the driver was stressed
      under high "queue full" loads.
    - The completion code assumed that it was always called with
      the sequencer running.  This may not be the case in timeout
      processing where completions occur manually via
      ahd_pause_and_flushwork().
    - With this scheme, the extra expense of clearing critical
      sections is avoided since the sequencer will only self pause
      once all pending selections have cleared and it is not in
      a critical section.

 o Revert ahd_pause_and_flushwork() behavior so that ENSELO can
   be cleared.  This makes ahd_pause_and_flushwork() more effective
   when the bus is hung.

 o Correct "Unexpected PKT Busfree" error observed under high
   tag loads.

 o Perform a few firmware optimizations
 o Correct the packetized status handler so that
   it can handle CRC errors during status data packets.

 o Auto disable PCI parity error reporting after 10 parity errors
   are observed.  The user is given a loud warning message telling
   them that eiter a device plugged into their motherboard or their
   motherboard is not very healthy.

 o Correct type safty of option parsing logic
 o Make option toggling work correctly
 o Add "probe_eisa_vlb" as an alias for the "no_probe" option so
   that there is a clearly defined name associated with the command
   line feature that allows eisa_vlb probes to be enabled/disabled
   in the aic7xxx driver.
 o PCI parity error checking defaults to being enabled.

 o Fix style nits.

 o Remove extra complexity and code duplication in processing
   the completeq now that the completeq can be run while holding
   both the ah?_lock and the done_lock.

 o Work around peculiarities in the scan_scsis routines
   that could, due to having duplicate devices on our
   host's device list, cause tagged queing to be disabled
   for devices added via /proc.

 o Correct channel information in our /proc output.

o Avoid pre-2.5.X mid-layer deadlock due to SCSI malloc fragmentation

For pre-2.5.X kernels, attempt to calculate a safe value
for our S/G list length.  In these kernels, the midlayer
allocates an S/G array dynamically when a command is issued
using SCSI malloc.  This list, which is in an OS dependent
format that must later be copied to our private S/G list, is
sized to house just the number of segments needed for the
current transfer.  Since the code that sizes the SCSI malloc
pool does not take into consideration fragmentation of the
pool, executing transactions numbering just a fraction of our
concurrent transaction limit with list lengths aproaching
AH?_NSEG in length will quickly depleat the SCSI malloc pool
of usable space.

Unfortunately, the mid-layer does not properly handle this
scsi malloc failure.  In kernels prior to 2.4.20, should
the device that experienced the malloc failure be idle and
never have any new I/O initiated (block queue is not "kicked"),
the process will hang indefinitely.  In 2.4.20 and beyond,
the disk experiencing the failure is marked as a "starved
device", but this only helps if I/O is initiated to or completes
on that HBA.  If the failure was induced by another HBA, and
no other I/O is pending on the HBA and no new transactions are
queued, we are still succeptible to the hang.  (Also note that
many 2.4.X kernels do not properly lock the "some_device_starved"
and "device_starved" fields calling into question their overall
effectiveness).

By sizing our S/G list to avoid SCSI malloc pool fragmentation,
we will hopefully avoid this deadlock at least for configurations
where our own HBAs are the only ones using the SCSI subsystem.

 o Correct failed-wait recovery code so that the controller's registers
   will not be accessed without pausing the controller first.

into overdrive.btc.adaptec.com:/usr/home/gibbs/bk/linux-2.5

 o Perform an audit on use of del_timer() and switch to del_timer_sync()
   where appropriate.
 o Remove the reboot notifier hook which is unused in 2.5.X.
 o Correct some driver unload bugs.

 o Correct bus hang on SE->LVD/LVD->SE tranceiver changes
 o Close a race condition in handling bad scsi status that could
   allow the driver to modify the waiting for selection queue while
   selections were enabled.
 o Perform an audit on use of del_timer() and switch to del_timer_sync()
   where appropriate.
 o Remove the reboot notifier hook which is unused in 2.5.X.
 o Correct some driver unload bugs.

to avoid casting problems with different architectures.

magic C promotion to silently do so for us.

was the first file tested with my type checker with the anal
pointer attribute checking turned on.

user space access functions. This allows the type checker
to check proper usage.

checking, these end up being no-ops, but they get enabled
by the type checker as special address_space attributes.

There is a stunning bug.

Previously, it was done automatically by the `reti' isntruction upon
returning from the kernel, but that doesn't do the correct thing in
various cases, for instance if there's a context switch, or a softirq.

Allows for the non standard cascade