and here is the patch. Submit it please. Thank you!
BTW, there is a new option "NDGBPORTS". By default it is equal to
NDGB*16 and means the number of ports of all Digiboards for which the
tty structures are reserved. It can be set to the real value in config-file
like:
options "NDGBPORTS=8"
Submitted by: Serge A. Babkin <babkin@hq.icb.chel.su>
scheduled for demolition. This is a first step: get rid of if_zereg.h,
by adding the five extra definitions to if_edreg.h.
Also add some definitions which will become needed when if_ze.c gets
replaced entirely by pccard and if_ed.c. (this is a 2.1.0 candidate)
with the driver's stability now. I've not had a single problem with it for
weeks.. All that remains is a bit of performance tuning, and finishing
the manpages.
Add prototypes. Use static for function definitions to match existing
prototypes. Otherwise leave functions that should be static as extern.
TODO: declare everthing except sidriver and siintr as static. I use
some new cdevs registration functions to do this for syscons and pcvt.
Fix siintr() to match its prototype in ioconf.c (don't return anything).
This may break the eisa support, but Julian says that eisa interrupts
never worked anyway.
(EISA support was never tested anyway - Peter)
Submitted by: bde
the first one in the config has priority. They can be switched using
userconfig().
i386/i386/conf.c:
Initialize the shared syscons/pcvt cdevsw entry to `nx'.
Add cdevsw registration functions.
Use devsw functions of the correct type if they exist.
i386/i386/cons.c:
Add renamed syscons entry points to constab.
i386/i386/cons.h:
Declare the renamed syscons entry points.
i386/i386/machdep.c:
Repeat console initialization after userconfig() in case the current
console has become wrong. This depends on cn functions not wiring down
anything important.
sys/conf.h:
Declare new functions.
i386/isa/isa.[ch]:
Add a function to decide which display driver has priority. Should be
done better.
i386/isa/syscons.c:
Rename pccn* -> sccn*.
Initialize CRTC start address in case the previous driver has moved it.
i386/isa/syscons.c, i386/isa/pcvt/*
Initialize the bogusly shared variable Crtat dynamically in case the
stored value was changed by the previous driver.
Initialize cdevsw table from a template.
Don't grab the console if another display driver has priority.
i386/isa/syscons.h, i386/isa/pcvt/pcvt_hdr.h:
Don't externally declare now-static cdevsw functions.
i386/isa/pcvt/pcvt_hdr.h:
Set the sensitive hardware flag so that pcvt doesn't always have lower
priority than syscons. This also fixes the "stupid" detection of the
display after filling the display with text.
i386/isa/pcvt/pcvt_out.c:
Don't be confused the off-screen cursor offset 0xffff set by syscons.
kern/subr_xxx.c:
Add enough nxio/nodev/null devsw functions of the correct type for syscons
and pcvt.
changes to allow devices that don't probe (e.g. /dev/mem)
to create devfs entries
this required giving 'configure' its own SYSINIT entry
so we could duck in just before it with a DEVFS init
and some device inits..
my devfs now looks like:
./misc
./misc/speaker
./misc/mem
./misc/kmem
./misc/null
./misc/zero
./misc/io
./misc/console
./misc/pcaudio
./misc/pcaudioctl
./disks
./disks/rfloppy
./disks/rfloppy/fd0.1440
./disks/rfloppy/fd1.1200
./disks/floppy
./disks/floppy/fd0.1440
./disks/floppy/fd1.1200
also some sligt cleanups.. DEVFS needs a lot of work
but I'm getting back to it..
This is still very green, but I have managed to get my modem working.
Lots of work still to do, but now at least we can commit it. /phk
Reviewed by: phk
Submitted by: Andrew McRae <andrew@mega.com.au>
Implement the slip/ppp "hotchar" detection to improve latency
Debug the L_RINT bypass code..
Fix an interesting feature that caused 8-bit chars to loose their top bit
in some circumstances..
This finishes the remaining outstanding problems that I'm aware of, with
the exception of efficiency... Optimizing can come later after it's fully
debugged.
actually a timeout only. The existing behaviour caused a
mcd0: timeout getreply
at halt/reboot time.
Submitted by: graichen@sirius.physik.fu-berlin.de (Thomas Graichen)
moved to the driver proper, so that <machine/si.h> can be #included by user
programs without needing to include stuff from /sys/i386/isa..
Various (now) redundant features removed, eg: the locks on IXANY and HWFLOW
as these are now done with the "initial" and "lock" termios devices.
Note that it still (for reasons unknown) appears to be masking data to
7-bit with ppp - hence the cleanup to support the debugging via 'sicontrol'
This was originally ported to BSDI by Andy Rutter <andy@acronym.co.uk>.
At the end of the day, this code has very little in common with Andy's
version, or the Specialix SYSV version. Essentially it has been gradually
and almost completely rewritten, with LOTS of advice and inspiration from
Bruce Evans. There are a couple of missing bits still, but they are minor.
The user-mode "sicontrol" program is in sad shape and will come in soon.
Transparent printing died a timely death.. Maybe later..
Jeremy Rolls @ Specialix (Development directory) has confirmed this is OK
to distribute, and Andy personally sent me his version that I started from.
Although this driver stood up to a nasty stress-test in this form, I am not
confident that there are no nasty bugs lurking.
People are welcome to try it, but dont go out and buy one just yet.. :-)
And *DONT* use it on a mission-critical machine... This is ALPHA QUALITY!
for return values. It just so happens that in the cases where it is likely
to fail, it is okay to change the M_NOWAIT to M_WAITOK -- and all will
be well. This problem was manfest as a panic very regularly on a 4MB
system right after bootup.
to replace the very poor, original implementation of Scatter/Gather operations.
Use a bit (that was freed up with the rewrite above) in the SCB control byte
to designate commands that should allow disconnection. The kernel driver
makes this decision now instead of the sequencer since the sequencer can't
do the indexing very efficiently.
This commit drops the sequencer from 426 instructions to 390 most likely
freeing enough space to do a target mode implementation.
The first could occur because the original code would continue to reset
the SCSIID register while waiting for a selection. This could potentially
conflict with a reconnect since a successfull reconnect will also set the
SCSIID register. The fix is to use a separate wait loop after starting
a selection (as was done a few revisions ago).
The second probably never happens, but it was possible for a target to
reconnect while there was a pending SCB on the waiting list and not get
noticed. The fix was to remove a supurflous check of the scb waiting
list.
hardware. Set the sleep-on flag for the address so there is more
than a small chance that the sleep address is actually used (this
used to work by timing out). Don't bother clearing the sleep-on
flag after a timeout here or elsewhere since leaving it set just
generates a few null calls to wakeup().
Introduce TS_CONNECTED and TS_ZOMBIE states. TS_CONNECTED is set
while a connection is established. It is set while (TS_CARR_ON or
CLOCAL is set) and TS_ZOMBIE is clear. TS_ZOMBIE is set for on to
off transitions of TS_CARR_ON that occur when CLOCAL is clear and
is cleared for off to on transitions of CLOCAL. I/o can only occur
while TS_CONNECTED is set. TS_ZOMBIE prevents further i/o.
Split the input-event sleep address TSA_CARR_ON(tp) into TSA_CARR_ON(tp)
and TSA_HUP_OR_INPUT(tp). The former address is now used only for
off to on carrier transitions and equivalent CLOCAL transitions.
The latter is used for all input events, all carrier transitions
and certain CLOCAL transitions. There are some harmless extra
wakeups for rare connection- related events. Previously there were
too many extra wakeups for non-rare input events.
Drivers now call l_modem() instead of setting TS_CARR_ON directly
to handle even the initial off to on transition of carrier. They
should always have done this. l_modem() now handles TS_CONNECTED
and TS_ZOMBIE as well as TS_CARR_ON.
gnu/isdn/iitty.c:
Set TS_CONNECTED for first open ourself to go with bogusly setting
CLOCAL.
i386/isa/syscons.c, i386/isa/pcvt/pcvt_drv.c:
We fake carrier, so don't also fake CLOCAL.
kern/tty.c:
Testing TS_CONNECTED instead of TS_CARR_ON fixes TIOCCONS forgetting to
test CLOCAL. TS_ISOPEN was tested instead, but that broke when we disabled
the clearing of TS_ISOPEN for certain transitions of CLOCAL.
Testing TS_CONNECTED fixes ttyselect() returning false success for output
to devices in state !TS_CARR_ON && !CLOCAL.
Optimize the other selwakeup() call (this is not related to the other
changes).
kern/tty_pty.c:
ptcopen() can be declared in traditional C now that dev_t isn't short.
Use input buffer watermarks of TTYHOG-512 (high) and (high)*7/8
(low) instead of TTYHOG/2 (high) and TTYHOG/5 (low) to agree with
some drivers. 512 is magic and some things depended on TTYHOG/2
>= TTYHOG-512 to work; now they depend on the 512 magic not changing
and TTYHOG-512 being significantly larger than 0. This should be
handled in ttsetwater().
Separate the decision about whether to do input flow control from
doing it. ttyblock() now just starts input flow control (hardware
and/or software) and there is a new function ttyunblock() to stop
it. The decisions are the same except for the watermark changes
and allowing for input expansion for PARMRK.
When flushing input, try harder at first to send a start character
if required, but give up if the first attempt fails.
cy.c, rc.c, sio.c:
Simplify: let ttyinput() handle input flow control if it is not
being bypassed. Use ttyblock() to start flow control otherwise.
rc.c:
Use same input flow control test as elsewhere: test in a more
efficient order and start flow control at >= highwater instead of
at > highwater.
essential when I fix excessive wakeups for output-below-low-water.
In cy.c and sio.c, wake up via the driver start routine to also
eliminate duplicated code involving the clearing of TS_TTSTOP.
Always (except in code to be replaced soon) call driver start
routine directly instead of going through ttstart().
ttwwakeup(). The conditions for doing the wakeup will soon become
more complicated and I don't want them duplicated in all drivers.
It's probably not worth making ttwwakeup() a macro or an inline
function. The cost of the function call is relatively small when
there is a process to wake up. There is usually a process to wake
up for large writes and the system call overhead dwarfs the function
call overhead for small writes.
were two races:
- q_to_b() might unexpectedly return 0 (e.g, after a keyboard signal
flushes the output queue and isn't echoed). ansi_put() interprets
0 bytes as 4GB...
- more output (e.g. for echoes) might arrive afer q_to_b() returns 0.
Then scstart() returns presumably and the new output might not be
handled for a long time.
Remove unused function scxint().
Fix prototypes (foo() isn't a prototype).
syscons' output is now only about 4-5 times slower than I want.
It loses a factor of 2 for scrolling output by unnecessarily copying
the screen buffer, a factor of 4/3 for dumb OPOST processing, and
a factor of 3/2 for clist processing.
- use pseudo-dma
- provide the same features and interface as sio
- support multiple boards
- fix bugs.
Some compile-time configuration constants are set to support higher
speeds and Cyclom-16Y's at a 30% relative cost in efficiency.
Cyclom-16Y support is untested.
form to do this than it is relying on individual subroutines (the logic
in epioctl is itself very minimal). Ideally, unnecessary splimp()'s should
now be removed if they exist; I'll leave this for a later date (a complete
code review of the driver needs to be done). Fixes a bug I noticed that
would show up when ifconfig'ing the interface down.
is needed for 3940 support.
Have tagged commands look to see if a target is "busy" with a non tagged
command before executing. This prevents overlapped tagged and non tagged
commands which can happen since request sense commands are not tagged.
people tend to assume their devices won't work if they see this
message, though it may indicate that those devices just don't
need any PCI driver (e.g. devices that emulate an ISA card, or
that have been initialised by the BIOS and need no further care).
no ports are active, provided there are no polled ports and no
`LOSESOUTINTS' ports. Do a little more in the interrupt handler instead.
This is a little less efficient if there are are many active ports but
a little more efficient otherwise. Polled ports are ones with no irq
specified (as before). `LOSESOUTINTS' ports are ones with 0x08 set in
their config flags. Unless this flag is set, it will now take up to one
second to recover from lost output interrupts, if any. Some 8250s and
16450s lose output interrupts.
Improve output buffering: copy the clist buffer to 2 linear buffers if
necessary and possible instead of to 1. Handle an arbitrary queue of
buffers in the interrupt handler. Check for waking up sleepers after
copying characters out of the clist buffer instead of before.
Delay translation of TIOCM_DTR to MCR_DTR etc. so that the top level
routines are more machine independent.
Fix bogus device register in unused code.
etc.). The tulip_start routine was rewritten to use less stack space (I've
been having problems with wcarchive overflowing the stack and this should
help a little). This version also has preliminary NetBSD support.
Rod Grimes helped in testing this version of the driver. Thanks Rod. It's
additionally been extensively tested here and on wcarchive.
Submitted by: Matt Thomas
to most users (the wrong length is passed to ether_input). The
second is more serious. The multicast hash algorithm uses the wrong
(low) bits instead of the right (high) bits. This is only an issue
if you use >12 multicast addresses but if you are using IP multicast
then it might affect you...
Submitted by: Matt Thomas
thrown out if bpfilter support and no BPF listener. (submitted by Bill
Fenner)
Removed unused variable and changed another from a stack variable to a
static - the variable was a rather large array of structs that consumed
a lot of stack space. (me)
1) If a target initiated a sync negotiation with us and happened to chose a
value above 15, the old code inadvertantly truncated it with an "& 0x0f".
If the periferal picked something really bad like 0x32, you'd end up with
an offset of 2 which would hang the drive since it didn't expect to ever
get something so low. We now do a MIN(maxoffset, given_offset).
2) In the case of Wide cards, we were turning on sync transfers after a
sucessfull wide negotiation. Now we leave the offset alone in the per
target scratch space (which implies asyncronous transfers since we initialize
it that way) until a syncronous negotation occurs.
3) We were advertizing a max offset of 15 instead of 8 for wide devices.
4) If the upper level SCSI code sent down a "SCSI_RESET", it would hang the
system because we would end up sending a null command to the sequencer. Now
we handle SCSI_RESET correctly by having the sequencer interrupt us when it
is about to fill the message buffer so that we can fill it in ourselves.
The sequencer will also "simulate" a command complete for these "message only"
SCBs so that the kernel driver can finish up properly. The cdplay utility
will send a "SCSI_REST" to the cdplayer if you use the reset command.
5) The code that handles SCSIINTs was broken in that if more than one type
of error was true at once, we'd do outbs without the card being paused.
The else clause after the busfree case was also an accident waiting to
happen. I've now turned this into an if, else if, else type of thing, since
in most cases when we handle one type of error, it should be okay to ignore
the rest (ie if we have a SELTO, who cares if there was a parity error on
the transaction?), but the section should really be rewritten after 2.0.5.
This fix was the least obtrusive way to patch the problem.
6) Only tag either SDTR or WDTR negotiation on an SCB. The real problem is
that I don't account for the case when an SCB that is tagged to do a particular
type of negotiation completes or SELTOs (selection timeout) without the
negotiation taking place, so the accounting of sdtrpending and wdtrpending
gets screwed up. In the wide case, if we tag it to do both wdtr and sdtr,
it only performs wdtr (since wdtr must occur first and we spread out the
negotiation over two commands) so we always have sdtrpending set for that
target and we never do a real SDTR. I fill properly fix the accounting
after 2.0.5 goes out the door, but this works (as confirmed by Dan) on
wide targets.
Other stuff that is also included:
1) Don't do a bzero when recycling SCBs. The only thing that must explicitly
be set to zero is the scb control byte which is done in ahc_get_scb. We also
need to set the SG_list_pointer and SG_list_count to 0 for commands that do
not transfer data.
2) Mask the interrupt type printout for the aic7870 case. The bit we were
using to determine interrupt type is only valid for the aic7770.
Submitted by: Justin Gibbs
the 802.3 frames generated by the DC21040 (which does automatic padding
of less-than-minimum frames) and the frames generated by the 'ed'
driver, I've found that there is indeed a bug in the size of "ETHER_MIN_LEN"
as reported by several people, John Hay being the most recent. The driver
was actually setting the length to 6+6+2+50 (64 bytes), which when adding
in the CRC (which is automatically appended to the frame and not included
in the length), the minimum frame is 4 bytes larger than it is supposed to
be. All of this is confirmed by tcpdump showing 50 bytes of data for
minimum frames from the 'ed' cards and 46 bytes from 'de' cards. This
analysis has also revealed that there is garbage in the un-filled in
portion at the end of the minimum frames from the 'ed' driver; I don't
plan to fix this.
The ``flags 1'' in the fdc line is now only needed for owners of an
Insight tape (perhaps there aren't any? Mine is disfunctional). All
other probes are safe wrt. to the motor-control line of floppy disk
drives. Document the flag in LINT finally.
fragmented.
Added support for Cogent em100 boards.
Fixed bug that caused BPF to toggle the card to UTP.
Various other improvements.
Submitted by: Matt Thomas and David Greenman
the adapter's selections. Many fast periferals were getting upset when
the sequencer decided to rearbitrate after the device had already won
arbitration. This also forced the creation of a list threaded through
the SCBs (since we don't have enough space anywhere else) of commands that
are awaiting reselection. This list is run down before any new transactions
from the input queue are allowed. The list is appened to whenever we begin
a selection (simple case since the selecting device is always at the head)
and by the kernel driver whenever a request sense occurs. In the common
case, the list is only one element long, but when a reselection wins out
over a selection and that reselection generates a request sense, the
outstanding selection required for the retreval of the sense code grows
the list. On machines with many targets, this might cause the list to grow
large, so this solution, which will allow up to the maximum number of I/O
requests capible of the card elements in the list, was chosen. The list
manipulation is trivial and adds three sequencer instructions of overhead
to the selection phase.
This fixes the "target busy" errors from micropolis drives and the bursty
I/O problem when performing I/O between a Quantum Grand Prix and any other
device. I anticipate that this will correct many of the problems that
have been reported with this driver.
Reviewed by: Wcarchive and David Greenman
don't expect this to work yet.. but at least they're here..
(hey this cvs stuff is fun!)
activate with a line exactly like the isa line in the config file,
(but specifying eisa :)
patches to come..
got a 2.2 version DC21040 chip in my SMC ethernet card! He suggests bumping
the check all the way down to 2.0 since it's pre-2.0 we're actually guarding
against.
Submitted by: Matt Thomas <matt@lkg.dec.com>
is identical to the older version, just the copyright has changed. Many
thanks go to Dean Gehnert of the Linux camp who went the extra mile to make
this happen.
Other changes:
Update assembler man page to include the -v and -D options
Merge in Dean's latest changes to the assembler
Have the sequencer do a MSG_REJECT when the negotiated syncronous rate
is lower than the adapter supports. This forces asyncronous mode which
is faster at these rates anyway.
This code will be moved shortly to the non-gpld portion of the tree.
Dropping into the debugger when a break comes down the serial line is a
>MISFEATURE (1st class)< and has been put under it's own #ifdef. This
should be a magic sequence of chars instead.
For those where it was easy, drivers were also fixed to call
dev_attach() during probe rather than attach (in keeping with the
new design articulated in a mail message five months ago). For
a few that were really easy, correct state tracking was added as well.
The `fd' driver was fixed to correctly fill in the description.
The CPU identify code was fixed to attach a `cpu' device. The code
was also massively reordered to fill in cpu_model with somethingremotely
resembling what identifycpu() prints out. A few bytes saved by using
%b to format the features list rather than lots of ifs.
old type (stty) ioctls can easily bypass locking bits.
It involves manual conversion from old ioctls to new ones,
large piece of code duplicated from tty_compat.c
after ttioctl too, because it can change t_line.
Remove (TS_CNTTB | TS_LNCH) test, it is always inherits from
old tty mode and can't be reach in currently setted mode.
old value.
Remove unnecessary check for active messages in setup SCB. This same test
would also jump to p_mesgin_done which would "ACK" an extra time possibly
confusing the target.
Tell the kernel driver whenever we send an ABORT_TAG message.
- Report valid residual byte counts. We actually pause the sequencer
when the residual is non-zero. I thought about using DMA to do this,
bus sequencer program space is tight.
- Fix embarassing off by one error in the computation of a 2's
compliment variable. This was most likely the cause of the
many problems reported with the tagged queuing code.
- Handle "MAX_SYNC" as a special case (ie we are the ones starting
the sync negotiation sequence). This was done so that the target
scratch area can be initialed to 0 offset (asyncronous transfers)
safely. The initialization to 0 (was 15) is necessary since in
some cases a Wide negotiation could run into problems if SCSIRATE
was set wrong and we went into data(in/out).
- Trim the DMA routines a little by using some procedures. Net
effect is more functionality with 3 less instructions after this
update.
- Toggle the WIDEODD bit of the DFCNTRL whenever this is not the
last SG block. It has no effect in the 8bit bus configuration,
but in the Wide configuration ensures that the overlap byte is
held in the SCSI block if the transfer is odd so it will end
up in the next SG (the correct behavior).
* to reduce the number of adapter failures. Transceiver select
* logic changed to use value from EEPROM. Autoconfiguration
* features added.
Submitted by: "Serge A. Babkin" <babkin@hq.icb.chel.su>
update what has actually been touched. This should speed up
screen access on slow hardware.
Introduced setting of "destructive" cursor size, much like
the old hardware cursor.
if (tp->t_line != 0)
test when CS_ODONE, it fails for NTTYDISC, use
if (linesw[tp->t_line].l_start != ttstart)
instead.
Reviewed by:
Submitted by:
Obtained from:
CVS:
BREAK/parity/framing errors.
Term "correctly" assumes POSIX spec. and 4.4 ttyinput() behaviour.
1) Discard BREAK/parity at interrupt level when apropriate IGN*
is set in iflag. It helps "raw" mode works even IGN* is set.
2) Zero parity (if INPCK) and framing directly in buffer
before passing it to b_to_q() in "raw" mode.
Efficency:
interrupt level: if no error occurse, only two "test" commands added
"raw" mode: buf scan incc times for parity/framing added
Reviewed by:
Submitted by:
Obtained from:
CVS:
Report floppy/tape units on seperate lines as fdX:/ftX: to correct lots of
ways the current scheme failed to end the output with \n.
Add controller and/or drive designator to the fron of several messages
that come from this drive. [It's not fun to track down driver messages
using grep over the source tree.]
Reviewed by: joerg
include <pci/pcivar.h> without including <sys/devconf.h> and other
drivers include <pci/pcivar.h> before including <sys/devconf.h> if
certain identifiers are defined.
The devconf headers have convoluted interdependencies. <sys/devconf.h>
includes <machine/devconf.h> which includes <pci/pcivar.h>. Most
drivers include <sys/devconf.h> so even isa drivers depend on
<pci/pcivar.h>. For similar reasons, most drivers depend on another
pci header, on an isa header and on two scsi headers.
NOT derived from the Linux code and is thus not GPL'd. It is the author's
express wish that the GPL copyrighted version be removed and this BSD copyright
version take its place. Considering our own stance on this, I'm certainly
not going to argue! [Note to NetBSD folks: You're free to grab it now :-)]
Submitted by: Mikael Hybsch <micke@dynas.se>
#include <i386/isa/isa.h>
return IO_EISASIZE instead of hard coded 0x1000.
if_ep.c:
Remove commented out disabling of interrupts that gave a
"comment withing a comment" warning.
1) Supports PCI to PCI bridge devices (and tries to initialise them,
even if the BIOS is brain dead).
2) Supports shared PCI interrupts. Interrupt handlers now MUST return
'0' if they found nothing to do, '1' otherwise.
New features tested with i486 systems based on the Intel Saturn and
a DEC 4channel Ethernet card only, but expected to work on most systems.
The option PCI_REMAP has been removed !
Submitted by: Wolfgang Stanglmeier <wolf@kintaro.cologne.de>
a device specific shutdown routine for devconf. Assign the value of this
to the kern_devconf struct. Implement a device shutdown routine for if_de
that disables the device. This will stop the device from corrupting memory
after a reboot.
Let "grey delete" be a function key (default is 0x7f)
Fix the xor cursor again..
Made the backspace key generate del as default
Made CTRL-space generate nul as default.
(a) bring back ttselect, now that we have xxxdevtotty() it isn't dangerous.
(b) remove all of the wrappers that have been replaced by ttselect
(c) fix formatting in syscons.c and definition in syscons.h
(d) add cxdevtotty
NOT DONE:
(e) make pcvt work... it was already broken...when someone fixes pcvt to
link properly, just rename get_pccons to xxxdevtotty and we're done
DEC 21050 chip in particular, don't have specs of other such chips).
This should add support for Multiple-Ethernet PCI cards (e.g. Znyx 314).
Reviewed by: se
Submitted by: <wolf@kintaro.cologne.de> Wolfgang Stanglmeier
is close to 1000000 / 960 usec so the confusion probably didn't matter.
Test for COMCONSOLE before testing for RB_SERIAL so that the RB_SERIAL
test can be optimized away if COMCONSOLE is 1.
Simplify and Uniformize style of previous commit.
(b) add a function callback vector to tty drivers that will return a pointer
to a valid tty structure based upon a dev_t
(c) make syscons structures the same size whether or not APM is enabled so
utilities don't crash if NAPM changes (and make the damn kernel compile!)
(d) rewrite /dev/snp ioctl interface so that it is device driver and i386
independant
