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.
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.
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.
to access it. setdelayed() actually ORs the bits in `idelayed' into
`ipending' and clears `idelayed'.
Call setdelayed() every (normal) clock tick to convert delayed
interrupts into pending ones.
Drivers can set bits in `idelayed' at any time to schedule an interrupt
at the next clock tick. This is more efficient than calling timeout().
Currently only software interrupts can be scheduled.
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.
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.
