return a struct device * of attached device, or NULL if device attach failed,
rather than 1/0 for success/failure, so that code that bus code which needs
to know what the child device is doesn't have to open-code a hacked variant
of config_found(). Make config_attach() return struct device *, rather than
void, to facilitate that.
* Add an ACB_RESET flag, so that a BUS DEVICE RESET can be queued within the
driver.
* If ACB_ABORT or ACB_RESET is set during reselection, schedule a message and
assert ATN.
* Optimize aic_datain_pio(), aic_dataout_pio() and aicintr() somewhat.
* Schedule a timeout only when we select the target, so that commands can't
time out prematurely.
temporarily revert bus config order back to isa->eisa->pci
until port allocation/accounting is ready (XXX).
works around problem of the if_ep driver's probe function trashing
an adaptec 2940 if the BIOS maps it in at port 0xf000. (the
BIOS on my new P166 does this, ... the BIOS on my P133's does not).
without this the P166 system will reset as soon as spl0() is called
(autoconf.c) making it impossible to install the OS.
influence from the old driver (written by Stefan Grefen) and from
an autochanger driver written by the Systems Programming Group at the
University of Utah Computer Science Department (currently residing
in src/sys/arch/hp300/dev/ac.c).
1) If we get an unexpected disconnect, issue a REQUEST SENSE, as recommended
by the SCSI-2 spec. If the target created a contingent allegiance condition,
this will clear it. Also, if it happened while sending a SDTR or WDTR message,
disable negotiation for that target.
2) Since some lame devices still don't deal correctly, make sure we deassert
ATN if our last message out is interrupted. If we get a MESSAGE PARITY ERROR,
we'll reassert ATN anyway. This should ensure that we never have to send a
MESSAGE NO OPERATION.
3) Set AIC_ABORTING only when actually sending a BUS DEVICE RESET or ABORT,
so we get better error detection.
4) Other internal reorganization of no consequence.
