linux-imx/drivers/char/ChangeLog

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.)