Subversion Repositories or1k

2001-08-11  Tim Waugh  <twaugh@redhat.com>

        * serial.c (get_pci_port): Deal with awkward Titan cards.

1998-08-26  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * serial.c (rs_open): Correctly decrement the module in-use count
                on errors.

Thu Feb 19 14:24:08 1998  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * tty_io.c (tty_name): Remove the non-reentrant (and non-SMP safe)
                version of tty_name, and rename the reentrant _tty_name
                function to be tty_name.
                (tty_open): Add a warning message stating callout devices
                are deprecated.

Mon Dec  1 08:24:15 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * tty_io.c (tty_get_baud_rate): Print a warning syslog if the
                tty->alt_speed kludge is used; this means the system is
                using the deprecated SPD_HI ioctls.

Mon Nov 24 10:37:49 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * serial.c, esp.c, rocket.c: Change drivers to take advantage of
                tty_get_baud_rate().
        
        * tty_io.c (tty_get_baud_rate): New function which computes the
                correct baud rate for the tty.  More factoring out of
                common code out of the serial driver to the high-level tty
                functions....

Sat Nov 22 07:53:36 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * serial.c, esp.c, rocket.c: Add tty->driver.break() routine, and
                allow high-level tty code to handle the break and soft
                carrier ioctls.
        
        * tty_ioctl.c (n_tty_ioctl): Support TIOCGSOFTCAR and
                TIOCSSOFTCAR, so that device drivers don't have to support
                it.

        * serial.c (autoconfig): Change 16750 test to hopefully eliminate
                false results by people with strange 16550As being
                detected as 16750s.  Hopefully 16750s will still be
                detected as 16750, and other weird UARTs won't get poorly
                autodetected.  If this doesn't work, I'll have to disable
                the auto identification for the 16750.

        * tty_io.c (tty_hangup): Now actually do the tty hangup
                processing during the timer processing, and disable
                interrupts while doing the hangup processing.  This avoids
                several nasty race conditions which happened when the
                hangup processing was done asynchronously.
                (tty_ioctl): Do break handling in the tty driver if
                driver's break function is supported.  
                (tty_flip_buffer_push): New exported function which should
                be used by drivers to push characters in the flip buffer
                to the tty handler.  This may either be done using a task
                queue function for better CPU efficiency, or directly for
                low latency operation.

        * serial.c (rs_set_termios): Fix bug rs_set_termios when
                transitioning away from B0, submitted by Stanislav
                Voronyi. 

Thu Jun 19 20:05:58 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * serial.c (begin_break, end_break, rs_ioctl): Applied patch
                to support BSD ioctls to set and clear the break
                condition explicitly.

        * console.c (scrup, scrdown, insert_line, delete_line): Applied
                fix suggested by Aaron Tiensivu to speed up block scrolls
                up and down.

        * n_tty.c (opost_block, write_chan): Added a modified "fast
                console" patch which processes a block of text via
                "cooking" efficiently.

Wed Jun 18 15:25:50 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * tty_io.c (init_dev, release_dev): Applied fix suggested by Bill
                Hawes to prevent race conditions in the tty code.

        * n_tty.c (n_tty_chars_in_buffer): Applied fix suggested by Bill
                Hawes so that n_tty_chars_in_buffer returns the correct
                value in the case when the tty is in cannonical mode.  (To
                avoid a pty deadlock with telnetd.)

Thu Feb 27 01:53:08 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * serial.c (change_speed): Add support for the termios flag
                CMSPAR, which allows the user to select stick parity.
                (i.e, if PARODD is set, the parity bit is always 1; if
                PARRODD is not set, then the parity bit is always 0).

Wed Feb 26 19:03:10 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * serial.c (cleanup_module): Fix memory leak when using the serial
                driver as a module; make sure tmp_buf gets freed!

Tue Feb 25 11:01:59 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * serial.c (set_modem_info): Add support for setting and clearing
                the OUT1 and OUT2 bits.  (For special case UART's, usually
                for half-duplex.)
                (autoconfig, change_speed): Fix TI 16750 support.

Sun Feb 16 00:14:43 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * tty_io.c (release_dev): Add sanity check to make sure there are
                no waiters on tty->read_wait or tty->write_wait.

        * serial.c (rs_init): Don't autoconfig a device if the I/O region
                is already reserved.

        * serial.c (serial_proc_info): Add support for /proc/serial.

Thu Feb 13 00:49:10 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * serial.c (receive_chars): When the UART repotrs an overrun
                condition, it does so with a valid character.  Changed to
                not throw away the valid character, but instead report the
                overrun after the valid character.

        * serial.c: Added new #ifdef's for some of the advanced serial
                driver features.  A minimal driver that only supports COM
                1/2/3/4 without sharing serial interrupts only takes 17k;
                the full driver takes 32k.
                
Wed Feb 12 14:50:44 1997  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * vt.c:
        * pty.c: 
        * tty_ioctl.c: 
        * serial.c: Update routines to use the new 2.1 memory access
                routines.

Wed Dec  4 07:51:52 1996  Theodore Ts'o  <tytso@localhost.mit.edu>

        * serial.c (change_speed): Use save_flags(); cli() and
                restore_flags() in order to ensure we don't accidentally
                turn on interrupts when starting up the port.
                (startup): Move the insertion of serial structure into the
                IRQ chain earlier into the startup processing.  Interrupts
                should be off this whole time, but we eventually will want
                to reduce this window.

Thu Nov 21 10:05:22 1996  Theodore Ts'o  <tytso@localhost.mit.edu>

        * tty_ioctl.c (tty_wait_until_sent): Always check the driver
                wait_until_ready routine, even if there are no characters
                in the xmit buffer.  (There may be charactes in the device
                FIFO.)
                (n_tty_ioctl): Add new flag tty->flow_stopped which
                indicates whether the tty is stopped due to a request by
                the TCXONC ioctl (used by tcflow).  If so, don't let an
                incoming XOFF character restart the tty.  The tty can only
                be restarted by another TCXONC request.

        * tty_io.c (start_tty): Don't allow the tty to be restarted if
                tty->flow_stopped is true.

        * n_tty.c (n_tty_receive_char): If tty->flow_stopped is true, and
                IXANY is set, don't eat a character trying to restart the
                tty.

        * serial.c (startup): Remove need for MCR_noint from the
                async_struct structure.  Only turn on DTR and RTS if the
                baud rate is not zero.
                (change_speed): More accurately calculate the timeout
                value based on the word size.  Move responsibility of
                hangup when speed becomes B0 to rs_set_termios()
                (set_serial_info): When changing the UART type set the
                current xmit_fifo_size as well as the permanent
                xmit_fifo_size.
                (rs_ioctl): Fix TCSBRK (used by tcdrain) and TCSBRKP
                ioctls to return EINTR if interrupted by a signal.
                (rs_set_termios): If the baud rate changes to or from B0,
                this function is now responsible for setting or clearing
                DTR and RTS.  DTR and RTS are only be changed on the
                transition to or from the B0 state.
                (rs_close): Wait for the characters to drain based on
                info->timeout.  At low baud rates (50 bps), it may take a
                long time for the FIFO to completely drain out!
                (rs_wait_until_sent): Fixed timeout handling.  Now
                releases control to the scheduler, but checks frequently
                enough so that the function is sensitive enough to pass
                the timing requirements of the NIST-PCTS.
                (block_til_ready): When opening the device, don't turn on
                DTR and RTS if the baud rate is B0.

Thu Nov 14 00:06:09 1996  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * serial.c (autoconfig): Fix autoconfiguration problems;
                info->flags wasn't getting initialized from the state
                structure.  Put in more paranoid test for the 16750.

Fri Nov  8 20:19:50 1996  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * n_tty.c (n_tty_flush_buffer): Only call driver->unthrottle() if
                the tty was previous throttled.
                (n_tty_set_termios, write_chan): Add changes suggested by
                        Simon P. Allen to allow hardware cooking.

        * tty_ioctl.c (set_termios): If we get a signal while waiting for
                the tty to drain, return -EINTR.
        
        * serial.c (change_speed): Add support for CREAD, as required by
                POSIX.

Sat Nov  2 20:43:10 1996  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * serial.c: Wholesale changes.  Added support for the Startech
                16650 and 16650V2 chips.  (WARNING: the new startech
                16650A may or may not work!)  Added support for the
                TI16750 (not yet tested).  Split async_struct into a
                transient part (async_struct) and a permanent part
                (serial_state) which contains the configuration
                information for the ports.  Added new driver routines
                wait_until_sent() and send_xchar() to help with POSIX
                compliance.  Added support for radio clocks which waggle
                the carrier detect line (CONFIG_HARD_PPS).
        
        * tty_ioctl.c (tty_wait_until_sent): Added call to new driver
                function tty->driver.wait_until_sent(), which returns when
                the tty's device xmit buffers are drained.  Needed for
                full POSIX compliance.

                (send_prio_char): New function, called by the ioctl's
                TCIOFF and TCION; uses the new driver call send_xchar(),
                which will send the XON or XOFF character at high priority
                (and even if tty output is stopped).

Wed Jun  5 18:52:04 1996  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * pty.c (pty_close): When closing a pty, make sure packet mode is
                cleared.

Sun May 26 09:33:52 1996  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * vesa_blank.c (set_vesa_blanking): Add missing verify_area() call.

        * selection.c (set_selection): Add missing verify_area() call.

        * tty_io.c (tty_ioctl): Add missing verify_area() calls.

        * serial.c (rs_ioctl): Add missing verify_area() calls.
                (rs_init): Allow initialization of serial driver
                configuration from a module.

        * random.c (extract_entropy): Add missing verify_area call.
                Don't limit number of characters returned to
                32,768. Extract entropy is now no longer a inlined
                function.

                (random_read): Check return value in case extract_entropy
                returns an error.

                (secure_tcp_sequence_number): New function which returns a
                secure TCP sequence number.  This is needed to prevent some
                nasty TCP hijacking attacks.
        
                (init_std_data): Initialize using gettimeofday() instead of
                struct timeval xtime.

                (fast_add_entropy_word, add_entropy_word): Rename the
                inline function add_entropy_word() to
                fast_add_entropy_word().  Make add_entropy_word() be the
                non-inlined function which is used in non-timing critical
                places, in order to save space.

                (initialize_benchmark, begin_benchmark, end_benchmark): New
                functions defined when RANDOM_BENCHMARK is defined.  They
                allow us to benchmark the speed of the
                add_timer_randomness() call.

                (int_ln, rotate_left): Add two new inline functions with
                i386 optimized asm instructions.  This speeds up the
                critical add_entropy_word() and add_timer_randomness()
                functions, which are called from interrupt handlers.

Tue May  7 22:51:11 1996    <tytso@rsts-11.mit.edu>

        * random.c (add_timer_randomness): Limit the amount randomness
                that we estimate to 12 bits.  (An arbitrary amount).

                (extract_entropy): To make it harder to analyze the hash
                function, fold the hash function in half using XOR, and
                use the folded result as the value to emit to the user.
                Also, add timer randomness each pass through the
                exact_entropy call, to increase the amount of unknown
                values during the extraction process.

                (random_ioctl): Use IOR/IOW definitions to define the
                ioctl values used by the /dev/random driver.  Allow the
                old ioctl values to be used for backwards compatibility
                (for a limited amount of time).

Wed Apr 24 14:02:04 1996  Theodore Ts'o  <tytso@rsts-11.mit.edu>

        * random.c (add_timer_randomness): Use 2nd derivative as well to
                better estimate entropy.

                (rand_initialize): Explicitly initialize all the pointers
                to NULL.  (Clearing pointers using memset isn't portable.)
                Initialize the random pool with OS-dependent data.

                (random_write): Add sanity checking to the arguments to
                random_write(), so that bad arguments won't cause a kernel
                SEGV. 

                (random_read): Update the access time of the device inode
                when you return data to the user.

                (random_ioctl): Wake up the random_wait channel when there
                are only WAIT_INPUT_BITS available.  Add more paranoia
                checks to make sure entropy_count doesn't go beyond the
                bounds of (0, POOLSIZE).  Add a few missing verify_area
                checks.  Add support for the RNDCLEARPOOL ioctl, which
                zaps the random pool.

                (add_timer_randomness): Wake up the random_wait
                channel only when there are WAIT_INPUT_BITS available.

                (random_select): Allow a random refresh daemon process to
                select on /dev/random for writing; wake up the daemon when
                there are less than WAIT_OUTPUT_BITS bits of randomness
                available.

Tue Apr 23 22:56:07 1996    <tytso@rsts-11.mit.edu>

        * tty_io.c (init_dev): Change return code when user attempts to
                open master pty which is already open from EAGAIN to EIO,
                to match with BSD expectations.  EIO is more correct
                anyway, since EAGAIN implies that retrying will be
                successful --- which it might be.... Eventually!!

        * pty.c (pty_open, pty_close): Fix wait loop so that we don't
                busy loop while waiting for the master side to open.
                Fix tty opening/closing logic.  TTY_SLAVE_CLOSED was
                renamed to TTY_OTHER_CLOSED, so that the name is more
                descriptive.  Also fixed code so that the tty flag
                actually works correctly now....

Mon Apr  1 10:22:01 1996    <tytso@rsts-11.mit.edu>

        * serial.c (rs_close): Cleaned up modularization changes.
                Remove code which forced line discipline back to N_TTY
                this is done in the tty upper layers, and there's no
                reason to do it here.  (Making this change also
                removed the requirement that the serial module access
                the internal kernel symbol "ldiscs".)

        * tty_io.c (tty_init): Formally register a tty_driver entry for
                /dev/tty (device 4, 0) and /dev/console (device 5, 0).
                This guarantees that major device numbers 4 and 5 will be
                reserved for the tty subsystem (as they have to be because
                of /dev/tty and /dev/console).  Removed tty_regdev, as
                this interface is no longer necessary.

Sun Mar 17 20:42:47 GMT 1996 <ah@doc.ic.ac.uk>

        * serial.c : modularisation (changes in linux/fs/device.c allow
                kerneld to automatically load the serial module).

        * Makefile, Config.in : serial modularisation adds.

        * tty_io.c : tty_init_ctty used by to register "cua" driver just
                for the /dev/tty device (5,0).  Added tty_regdev.
        
        * serial.c (shutdown, rs_ioctl) : when port shuts down wakeup processes
          waiting on delta_msr_wait. The TIOCMIWAIT ioctl returns EIO
          if no change was done since the time of call.

Sat Mar 16 14:33:13 1996 <aeb@cwi.nl>

        * tty_io.c (disassociate_ctty): If disassociate_ctty is called by
                exit, do not perform an implicit vhangup on a pty.

Fri Feb  9 14:15:47 1996    <tytso@rsts-11.mit.edu>

        * serial.c (block_til_ready): Fixed another race condition which
                happens if a hangup happens during the open.

Wed Jan 10 10:08:00 1996    <tytso@rsts-11.mit.edu>

        * serial.c (block_til_ready): Remove race condition which happened
                if a hangup condition happened during the setup of the
                UART, before rs_open() called block_til_ready().  This
                caused the info->count counter to be erroneously
                decremented.

        * serial.c (startup, rs_open): Remove race condition that could
                cause a memory leak of one page.  (Fortunately, both race
                conditions were relatively rare in practice.)

Tue Dec  5 13:21:27 1995    <tytso@rsts-11.mit.edu>

        * serial.c (check_modem_status, rs_ioctl): Support the new
                ioctl()'s TIOCGICOUNT, TIOCMIWAIT.  These allow an
                application program to wait on a modem serial register
                status bit change, and to find out how many changes have
                taken place for the MSR bits.

                (rs_write): Eliminate a race condition which is introduced
                if it is necessary to wait for the semaphore.

Sat Nov  4 17:14:45 1995    <tytso@rsts-11.mit.edu>

        * tty_io.c (tty_init): Move registration of TTY_MAJOR and
                TTY_AUX_MAJOR to the end, so that /proc/devices looks
                prettier. 

        * pty.c (pty_init): Use new major numbers for PTY master and slave
                devices.  This allow us to have more than 64 pty's.  We
                register the old pty devices for backwards compatibility.
                Note that a system should either be using the old pty
                devices or the new pty devices --- in general, it should
                try to use both, since they map into the same pty table.
                The old pty devices are strictly for backwards compatibility.

Wed Oct 11 12:45:24 1995    <tytso@rsts-11.mit.edu>

        * tty_io.c (disassociate_ctty): If disassociate_ctty is called by
                exit, perform an implicit vhangup on the tty.

        * pty.c (pty_close): When the master pty is closed, send a hangup
                to the slave pty.
                (pty_open): Use the flag TTY_SLAVE_CLOSED to test to see
                if there are any open slave ptys, instead of using
                tty->link->count.  The old method got confused if there
                were processes that had hung-up file descriptors on the
                slave tty.

Tue May  2 00:53:25 1995    <tytso@rsx-11.mit.edu>

        * tty_io.c (tty_set_ldisc): Wait until the output buffer is
                drained before closing the old line discipline --- needed
                in only one case: XON/XOFF processing.

        * n_tty.c (n_tty_close): Don't bother waiting until the output
                driver is closed; in general, the line discipline
                shouldn't care if the hardware is finished
                transmitting before the line discipline terminates.

        * tty_io.c (release_dev): Shutdown the line discipline after
                decrementing the tty count variable; but set the
                TTY_CLOSING flag so that we know that this tty structure
                isn't long for this world.

        * tty_io.c (init_dev): Add sanity code to check to see if
                TTY_CLOSING is set on a tty structure; if so, something
                bad has happened (probably a line discipline close blocked
                when it shouldn't have; so do a kernel printk and then
                return an error).

Wed Apr 26 10:23:44 1995  Theodore Y. Ts'o  <tytso@localhost>

        * tty_io.c (release_dev): Try to shutdown the line discipline
                *before* decrementing the tty count variable; this removes
                a potential race condition which occurs when the line
                discipline close blocks, and another process then tries
                open the same serial port.

        * serial.c (rs_hangup): When hanging up, flush the output buffer
                before shutting down the UART.  Otherwise the line
                discipline close blocks waiting for the characters to get
                flushed, which never happens until the serial port gets reused.

Wed Apr 12 08:06:16 1995  Theodore Y. Ts'o  <tytso@localhost>

        * serial.c (do_serial_hangup, do_softint, check_modem_status,
                rs_init):  Hangups are now scheduled via a separate tqueue
                structure in the async_struct structure, tqueue_hangup.
                This task is pushed on to the tq_schedule queue, so that
                it is processed synchronously by the scheduler.

Sat Feb 18 12:13:51 1995  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_io.c (disassociate_ctty, tty_open, tty_ioctl): Clear
                current->tty_old_pgrp field when a session leader
                acquires a controlling tty, and after a session leader
                has disassociated from a controlling tty.

Fri Feb 17 09:34:09 1995  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (rs_interrupt_single, rs_interrupt, rs_interrupt_multi): 
                Change the number of passes made from 64 to be 256,
                configurable with the #define RS_ISR_PASS_LIMIT.

        * serial.c (rs_init, set_serial_info, get_serial_info, rs_close):
                Remove support for closing_wait2.  Instead, set
                tty->closing and rely on the line discipline to prevent
                echo wars.

        * n_tty.c (n_tty_receive_char):  IEXTEN does not need to be
                enabled in order for IXANY to be active.

                If tty->closing is set, then only process XON and XOFF
                characters.

Sun Feb 12 23:57:48 1995  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (rs_timer): Change the interrupt poll time from 60
                seconds to 10 seconds, configurable with the #define
                RS_STROBE_TIME.

        * serial.c (rs_interrupt_multi, startup, shutdown, rs_ioctl,
                set_multiport_struct, get_multiport_struct): Add
                provisions for a new type of interrupt service routine,
                which better supports multiple serial ports on a single
                IRQ.  

Sun Feb  5 19:35:11 1995  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_ioctl.c (n_tty_ioctl, set_termios, tty_wait_until_sent): 
        * serial.c (rs_ioctl, rs_close): 
        * cyclades.c (cy_ioctl, cy_close): 
        * n_tty.c (n_tty_close):  Rename wait_until_sent to
                tty_wait_until_sent, so that it's a better name to export
                in ksyms.c.

Sat Feb  4 23:36:20 1995  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (rs_close): Added missing check for closing_wait2 being
                ASYNC_CLOSING_WAIT_NONE.

Thu Jan 26 09:02:49 1995  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (rs_init, set_serial_info, get_serial_info,
                rs_close): Support close_wait in the serial driver.
                This is helpful for slow devices (like serial
                plotters) so that their outputs don't get flushed upon
                device close.  This has to be configurable because
                normally we don't want ports to be hung up for long
                periods of time during a close when they are not
                connected to a device, or the device is powered off.

                The default is to wait 30 seconds; in the case of a
                very slow device, the close_wait timeout should be
                lengthened.  If it is set to 0, the kernel will wait
                forever for all of the data to be transmitted.

Thu Jan 17 01:17:20 1995  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (startup, change_speed, rs_init): Add support to detect
                the StarTech 16650 chip.  Treat it as a 16450 for now,
                because of its FIFO bugs.

Thu Jan  5 21:21:57 1995  <dahinds@users.sourceforge.net>

        * serial.c: (receive_char): Added counter to prevent infinite loop
                when a PCMCIA serial device is ejected.

Thu Dec 29 17:53:48 1994    <tytso@rsx-11.mit.edu>

        * tty_io.c (check_tty_count): New procedure which checks
                tty->count to make sure that it matches with the number of
                open file descriptors which point at the structure.  If
                the number doesn't match, it prints a warning message.

Wed Dec 28 15:41:51 1994    <tytso@rsx-11.mit.edu>

        * tty_io.c (do_tty_hangup, disassociate_ctty): At hangup time,
                save the tty's current foreground process group in the
                session leader's task structure.  When the session leader
                terminates, send a SIGHUP, SIGCONT to that process group.
                This is not required by POSIX, but it's not prohibited
                either, and it appears to be the least intrusive way
                to fix a problem that dialup servers have with
                orphaned process groups caused by modem hangups.

Thu Dec  8 14:52:11 1994    <tytso@rsx-11.mit.edu>

        * serial.c (rs_ioctl): Don't allow most ioctl's if the serial port
                isn't initialized.

        * serial.c (rs_close): Don't clear the IER if the serial port
                isn't initialized. 

        * serial.c (block_til_ready): Don't try to block on the dialin
                port if the serial port isn't initialized.

Wed Dec  7 10:48:30 1994  Si Park (si@wimpol.demon.co.uk)
        * tty_io.c (tty_register_driver): Fix bug when linking onto
                the tty_drivers list. We now test that there are elements
                already on the list before setting the back link from the
                first element to the new driver.

        * tty_io.c (tty_unregister_driver): Fix bug in unlinking the
                specified driver from the tty_drivers list. We were not
                setting the back link correctly. This used to result in
                a dangling back link pointer and cause panics on the next
                call to get_tty_driver().

Tue Nov 29 10:21:09 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_io.c (tty_unregister_driver): Fix bug in
                tty_unregister_driver where the pointer to the refcount is
                tested, instead of the refcount itself.  This caused
                tty_unregister_driver to always return EBUSY.

Sat Nov 26 11:59:24 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_io.c (tty_ioctl): Add support for the new ioctl
                TIOCTTYGSTRUCT, which allow a kernel debugging program
                direct read access to the tty and tty_driver structures.

Fri Nov 25 17:26:22 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (rs_set_termios): Don't wake up processes blocked in
                open when the CLOCAL flag changes, since a blocking
                open only samples the CLOCAL flag once when it blocks,
                and doesn't check it again.  (n.b.  FreeBSD has a
                different behavior for blocking opens; it's not clear
                whether Linux or FreeBSD's interpretation is correct.
                POSIX doesn't give clear guidance on this issue, so
                this may change in the future....)

        * serial.c (block_til_ready): Use the correct termios structure to
                check the CLOCAL flag.  If the cuaXX device is active,
                then check the saved termios for the ttySXX device.
                Otherwise, use the currently active termios structure.

Sun Nov  6 21:05:44 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (change_speed): Add support for direct access of
                57,600 and 115,200 bps.

Wed Nov  2 10:32:36 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * n_tty.c (n_tty_receive_room): Only allow excess characters
                through if we are in ICANON mode *and* there are other no
                pending lines in the buffer.  Otherwise cut and paste over
                4k breaks.

Sat Oct 29 18:17:34 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (rs_ioctl, get_lsr_info): Added patch suggested by Arne
                Riiber so that user mode programs can tell when the
                transmitter shift register is empty.

Thu Oct 27 23:14:29 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_ioctl.c (wait_until_sent): Added debugging printk statements
                (under the #ifdef TTY_DEBUG_WAIT_UNTIL_SENT)  

        * serial.c (rs_interrupt, rs_interrupt_single, receive_chars,
                change_speed, rs_close): rs_close now disables receiver
                interrupts when closing the serial port.  This allows the
                serial port to close quickly when Linux and a modem (or a
                mouse) are engaged in an echo war; when closing the serial
                port, we now first stop listening to incoming characters,
                and *then* wait for the transmit buffer to drain.  

                In order to make this change, the info->read_status_mask
                is now used to control what bits of the line status
                register are looked at in the interrupt routine in all
                cases; previously it was only used in receive_chars to
                select a few of the status bits.

Mon Oct 24 23:36:21 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (rs_close): Add a timeout to the transmitter flush
                loop; this is just a sanity check in case we have flaky
                (or non-existent-but-configured-by-the-user) hardware.

Fri Oct 21 09:37:23 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_io.c (tty_fasync): When asynchronous I/O is enabled, if the
                process or process group has not be specified yet, set it
                to be the tty's process group, or if that is not yet set,
                to the current process's pid.

Thu Oct 20 23:17:28 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * n_tty.c (n_tty_receive_room): If we are doing input
                canonicalization, let as many characters through as
                possible, so that the excess characters can be "beeped".

Tue Oct 18 10:02:43 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (rs_start): Removed an incorrect '!' that was
                preventing transmit interrupts from being re-enabled in
                rs_start().  Fortunately in most cases it would be
                re-enabled elsewhere, but this still should be fixed
                correctly.

Sun Oct  9 23:46:03 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_io.c (do_tty_hangup): If the tty driver flags
                TTY_DRIVER_RESET_TERMIOS is set, then reset the termios
                settings back to the driver's initial configuration.  This
                allows the termios settings to be reset even if a process
                has hung up file descriptors keeping a pty's termios from
                being freed and reset.

        * tty_io.c (release_dev): Fix memory leak.  The pty's other
                termios structure should also be freed.

        * serial.c (rs_close, shutdown): Change how we wait for the
                transmitter to completely drain before shutting down the
                serial port.  We now do it by scheduling in another
                process instead of busy looping with the interrupts turned
                on.  This may eliminate some race condition problems that
                some people seem to be reporting.

Sun Sep 25 14:18:14 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_io.c (release_dev): When freeing a tty make sure that both
                the tty and the o_tty (if present) aren't a process's
                controlling tty.  (Previously, we only checked the tty.)

        * serial.c (change_speed): Only enable the Modem Status
                Interrupt for a port if CLOCAL is not set or CRTSCTS
                is set.  If we're not checking the carrier detect and
                CTS line, there's no point in enabling the modem
                status interrupt.  This will save spurious interrupts
                from slowing down systems who have terminals that
                don't support either line.  (Of course, if you want
                only one of CD and CTS support, you will need a
                properly wired serial cable.)

Thu Sep 22 08:32:48 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_io.c (do_SAK): Return if tty is null.

        * tty_io.c (_tty_name): Return "NULL tty" if the passed in tty is
                NULL.

Sat Sep 17 13:19:25 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_ioctl.c (n_tty_ioctl): Fix TIOCGLCKTRMIOS and
                TIOCSLCKTRMIOS, which were totally broken.  Remove
                extra indirection from argument; it should be a struct
                termios *, not a struct termios **.
                &real_tty->termios_locked should have been
                real_tty->termios_locked.  This caused us to be
                reading and writing the termios_locked structure to
                random places in kernel memory.  

        * tty_io.c (release_dev): Oops!  Forgot to delete a critical kfree
                of the locked_termios.  This leaves the locked_termios
                structure pointed at a freed object.  

Fri Sep 16 08:13:25 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * tty_io.c (tty_open): Don't check for an exclusive open until
                after the device specific open routine has been called.
                Otherwise, the serial device ref counting will be screwed
                up.

        * serial.c (rs_open, block_til_ready): Don't set termios structure
                until after block_til_ready has returned successfully.
                Modify block_til_ready to check the normal_termios
                structure directly, so it doesn't rely on termios being
                set before it's called.

Thu Sep 15 23:34:01 1994  Theodore Y. Ts'o  (tytso@rt-11)

        * serial.c (rs_close): Turn off interrupts during rs_close() to
                prevent a race condition with the hangup code (which
                runs during a software interrupt).

        * tty_io.c (release_dev): Don't free the locked_termios structure;
                its state must be retained across device opens.


        * tty_io.c (tty_unregister_driver): Added function to unregister a
                tty driver.  (For loadable device drivers.)