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.
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.
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.
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:
(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
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
Obtained from:
sio.c and sioreg.c changed to allow autodetecting the RB_SERIAL flag
passed by the boot blocks so that the kernel can switch to 'serial
console' mode automagically. 'options COMCONSOLE' can still be specified
to force the kernel to always use the serial port as a console.
CONUNIT and CONADDR can also be specified in the kernel config file
if the user wants to shift the console to a different port.
errors at a lower ipl. clist starvation problems can cause hundreds of
tty buffer overflows per second and logging them all amplified the
problems. This problem was less serious in 1.1.5.
Avoid a race in the check for starting a new block of output. com_events
was sometimes messed up and siopoll() looped endlessly. This bug was
introduced in 2.0.
Clean up previous 2 commits. Rename sio_registerdev() to sioregisterdev()
to match the (bad) surrounding naming conventions. There should be a
generic_registerdev().
