to 16 or 4 (depending on capabilities of adapter), as it was before
thorpej_scsipi integration
Waiting feedback to known whenever the problem with openings set to AHC_SCB_MAX
existed before.
This is a completely rewritten scsipi_xfer execution engine, and the
associated changes to HBA drivers. Overview of changes & features:
- All xfers are queued in the mid-layer, rather than doing so in an
ad-hoc fashion in individual adapter drivers.
- Adapter/channel resource management in the mid-layer, avoids even trying
to start running an xfer if the adapter/channel doesn't have the resources.
- Better communication between the mid-layer and the adapters.
- Asynchronous event notification mechanism from adapter to mid-layer and
peripherals.
- Better peripheral queue management: freeze/thaw, sorted requeueing during
recovery, etc.
- Clean separation of peripherals, adapters, and adapter channels (no more
scsipi_link).
- Kernel thread for each scsipi_channel makes error recovery much easier
(no more dealing with interrupt context when recovering from an error).
- Mid-layer support for tagged queueing: commands can have the tag type
set explicitly, tag IDs are allocated in the mid-layer (thus eliminating
the need to use buggy tag ID allocation schemes in many adapter drivers).
- support for QUEUE FULL and CHECK CONDITION status in mid-layer; the command
will be requeued, or a REQUEST SENSE will be sent as appropriate.
Just before the merge syssrc has been tagged with thorpej_scsipi_beforemerge
a happy code sweep (in the kernel!) and constified a random selection of
kernel objects. This changed the alignment of the previously-aligned-by-
accident seqprog array, and exposed a lurking bug. I can't decide if this
is good or bad.
and QUEUE FULL cases; this is already done for all BAD_STATUS cases.
Make sure to requeue the SCB in the above cases internally in the driver,
the SCSI layer doesn't know how to deal with it properly.
some devices may not be found if the BIOS (which would normally
do the reset at startup) is disabled. Should really be done from the SCSI
layer.
Implement the SCBUSIORESET ioctl.
timeout()/untimeout() API:
- Clients supply callout handle storage, thus eliminating problems of
resource allocation.
- Insertion and removal of callouts is constant time, important as
this facility is used quite a lot in the kernel.
The old timeout()/untimeout() API has been removed from the kernel.
field in the softc, instead of relying on NPCI > 0. This would
prevent things from compiling if PCI buses were in the config file,
but ahc was attached only to something else than the PCI bus.
wiz