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Updated for new sio driver

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This commit is contained in:
ache 1994-06-04 00:41:25 +00:00
parent 6a53927500
commit 7a9508d2f0
2 changed files with 394 additions and 154 deletions
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274
share/man/man4/man4.i386/sio.4
View File

@ -36,7 +36,7 @@
.\" from: com.4,v 1.1 1993/08/06 11:19:07 cgd Exp
.\" $Id: sio.4,v 1.10 1994/05/07 01:15:10 ache Exp $
.\"
.Dd February 9, 1994
.Dd June 3, 1994
.Dt SIO 4 i386
.Os FreeBSD
.Sh NAME
@ -50,14 +50,42 @@ For standard ports:
.Cd "device sio2 at isa? port" \&"IO_COM3\&" tty irq 5 vector siointr
.Cd "device sio3 at isa? port" \&"IO_COM4\&" tty irq 9 vector siointr
.sp
For multiport cards:
For AST compatible multiport cards with 4 ports:
.Cd "options" \&"COM_MULTIPORT\&"
.Cd "device sio4 at isa? port 0x2a0 tty irq 12 flags 0x701 vector siointr"
.Cd "device sio5 at isa? port 0x2a8 tty flags 0x701 vector siointr"
.Cd "device sio6 at isa? port 0x2b0 tty flags 0x701 vector siointr"
.Cd "device sio7 at isa? port 0x2b8 tty flags 0x701 vector siointr"
.Cd "device sio4 at isa? port 0x2a0 tty flags 0x701"
.Cd "device sio5 at isa? port 0x2a8 tty flags 0x701"
.Cd "device sio6 at isa? port 0x2b0 tty flags 0x701"
.Cd "device sio7 at isa? port 0x2b8 tty flags 0x701 irq 12 vector siointr"
.sp
Use 0x02 bit in flags field to disable FIFO on specified port.
For Boca Board compatible multiport cards with 8 ports:
.Cd "options" \&"COM_MULTIPORT\&"
.Cd "device sio4 at isa? port 0x100 tty flags 0xb05"
.Cd "..."
.Cd "device sio11 at isa? port 0x138 tty flags 0xb05 irq 12 vector siointr"
.sp
Meaning of \fBflags\fR:
.br
\fB0x0001\fR shared IRQs
.br
\fB0x0002\fR disable FIFO
.br
\fB0x0004\fR no AST/4 compatible IRQ control register
.br
\fB0x0080\fR disable diagnostics in probe
.br
\fB0x\fI??\fB00\fR minor number of master port
.sp
Minor numbering:
.br
0b\fIOLIMMMMM\fR
.br
call\fBO\fRut
.br
\fBL\fRock
.br
\fBI\fRnitial
.br
\fBMMMMMM\fRinor
.Sh DESCRIPTION
The
.Nm sio
@ -67,108 +95,199 @@ driver provides support for NS8250-, NS16450-, NS16550 and NS16550A-based
.Pf ( Tn CCITT
.Tn V.24 )
communications interfaces. The NS8250 and NS16450 have single character
buffers, the NS16550A has a 16 character FIFO buffer.
buffers, the NS16550A has 16 character FIFO input and output buffers.
.Pp
Input and output for each line may set to one of following baud rates;
50, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600,
19200, 38400, 57600, or 115200. Your hardware may limit your baud
rate choices.
.Pp
The driver supports `multiport' cards.
The driver supports `multiport' cards.
Multiport cards are those that have one or more groups of ports
that share a common IRQ and Interrupt Request register set per group.
Frequently 4 ports share 1 IRQ, some 8 port cards have 2 groups of 4 ports,
that share an Interrupt Request (IRQ) line per group.
Shared IRQs on different cards are not supported.
Frequently 4 ports share 1 IRQ; some 8 port cards have 2 groups of 4 ports,
thus using 2 IRQs.
Some cards allow the first 2 serial ports to have seperate IRQs per port
(as per DOS PC standard).
.sp
Some cards have an IRQ control register for each group.
Some cards require special initialization related to such registers.
Only AST/4 compatible IRQ control registers are supported.
Some cards have an IRQ status register for each group.
The driver does not require or use such registers yet.
To work, the control and status registers for a group, if any,
must be mapped to the scratch register (register 7)
of a port in the group.
Such a port is called a
.Nm master
port.
.sp
The
.Nm flags
keyword specifies for each
keyword may be used on each
.Nm device sio
line in the kernel configuration file,
whether the port is part of an IRQ sharing group, & if so,
which port is the master device for
the group (ie which port has the IRQ control registers).
The master device is the port which
has registers through which all interrupts of the port group are funneled.
All ports of a port group report pending interrupts using this
single register.
line in the kernel configuration file
to silence the probe
or to disable the FIFO on 16550A UARTs
(see the synopsis).
Disabling the FIFO should rarely be necessary
since the driver automatically adjusts the receiver
FIFO trigger level for low latency and high efficiency.
.sp
The master device is an integer embedded in the high byte of the
The
.Nm flags
bitfield, so all sio entries in the kernel config file that are part of a
multiport card must include the correct
.Nm flags
specification.
The bitwise assignment allows multiple port groups to
be configured in one system. It does
keyword
.Nm must
be used for all ports that are part of an IRQ sharing group.
One bit specifies IRQ sharing; another bit specifies whether the port does
.Nm not
imply that more than one port group (or card) can share
the same physical interrupt line!
require AST/4 compatible initialization.
The minor number of the device corresponding a master port
for the group is encoded as a bitfield in the high byte.
The same master port must be specified for all ports in a group.
.sp
The
.Nm irq
and
.Nm vector
specifications must be given for master ports
and for ports that are not part of an IRQ sharing group,
and not for other ports.
.Pp
In the synopsis the
In the synopsis,
.Nm flags 0x701
means that the 8th port (sio7) is the master
device (so the MSB of the flags), and that the ports are part of a
multiport card (the LSB of the flags, actually only the LS
.Nm bit
).
F.e. if you have only two standard ports in addition to multiport
card, this
.Nm flags
will be
.Nm 0x501
(assuming the control port is
.Nm sio5
).
port, and that the port is on a multiport card with shared IRQs
and an AST/4 compatible IRQ control register.
.sp
.Nm flags 0xb05
means that the 12th port (sio11) is the master
port, and that the port is on a multiport card with shared IRQs
and no special IRQ control register.
.Pp
Which port is the master device depends on the card type. Consult
the hardware documentation of your card.
Which port is the master port depends on the card type.
Consult the hardware documentation of your card.
Since IRQ status registers are never used,
and IRQ control registers are only used for AST/4 compatible cards,
and some cards map the control/status registers to all ports in a group,
any port in a group will sometimes do for the master port.
Choose a port containing an IRQ status register for forwards compatibility,
and the highest possible port for consistency.
.Pp
Serial ports controlled by the
Serial ports controlled by the
.Nm sio
driver can be used for both dialin and dialout.
The minor number of the dialout
port is 128 higher than that of the corresponding dialin port. Use
.Xr stty 1
to enable or disable modem control as required by your setup.
driver can be used for both `callin' and `callout'.
For each port there is a callin device and a callout device.
The minor number of the callout device is 128 higher
than that of the corresponding callin port.
The callin device is general purpose.
Processes opening it normally wait for carrier
and for the callout device to become inactive.
The callout device is used to steal the port from
processes waiting for carrier on the callin device.
Processes opening it do not wait for carrier
and put any processes waiting for carrier on the callin device into
a deeper sleep so that they do not conflict with the callout session.
The callout device is abused for handling programs that are supposed
to work on general ports and need to open the port without waiting
but are too stupid to do so.
.Pp
While testing new cards & resolving card config DIP header &
.Nm sio flags
settings, to avoid coms. failure from lack of full modem DC level
settings on ports,
you are recommended to temporarily use syntax such as:
.Nm stty -f /dev/tty03 clocal
The
.Nm sio
driver also supports an initial-state and a lock-state control
device for each of the callin and the callout "data" devices.
The minor number of the initial-state device is 32 higher
than that of the corresponding data device.
The minor number of the lock-state device is 64 higher
than that of the corresponding data device.
The termios settings of a data device are copied
from those of the corresponding initial-state device
on first opens and are not inherited from previous opens.
Use
.Xr stty 1
in the normal way on the initial-state devices to program
initial termios states suitable for your setup.
.sp
The lock termios state acts as flags to disable changing
the termios state. E.g., to lock a flag variable such as
CRTSCTS, use
.Nm stty crtscts
on the lock-state device. Speeds and special characters
may be locked by setting the corresponding value in the lock-state
device to any nonzero value.
.sp
Correct programs talking to correctly wired external devices
work with arbitrary initial states and almost no locking,
but other setups may benefit from changing some of the default
initial state and locking the state.
E.g., CRTSCTS should be locked on for devices that support
RTS/CTS handshaking at all times and off for devices that don't
support it at all. CLOCAL should be locked on for devices
that don't support carrier. HUPCL may be locked off if you don't
want to hang up for reason. In general, very bad things happen
if something is locked to the wrong state, and things should not
be locked for devices that support more than one setting. The
CLOCAL flag on callin ports should be locked off for logins
to avoid certain security holes, but this needs to be done by
getty if the callin port is used for anything else.
.Sh FILES
.Bl -tag -width /dev/tty0? -compact
.Bl -tag -width /dev/ttyi0? -compact
.It Pa /dev/tty0?
for hardwired terminals
.It Pa /dev/ttyi0?
.It Pa /dev/ttyl0?
corresponding initial-state and lock-state devices
.El
.sp
or
.Bl -tag -width /dev/tty0? -compact
.sp
.Bl -tag -width /dev/ttyi0? -compact
.It Pa /dev/ttyd?
for dialin ports
for callin ports
.It Pa /dev/ttyid?
.It Pa /dev/ttyld?
corresponding callin initial-state and lock-state devices
.sp
.It Pa /dev/cua0?
for dialout ports
for callout ports
.It Pa /dev/cuai0?
.It Pa /dev/cual0?
corresponding callout initial-state and lock-state devices
.El
.sp
.Bl -tag -width /etc/rc.serial -compact
.It Pa /etc/rc.serial
examples of setting the initial-state and lock-state devices
.El
.Pp
The devices numbers are made from the set [0-9a-z] so that more than
The devices numbers are made from the set [0-9a-v] so that more than
10 ports can be supported.
/dev/tty0? and /dev/ttyd? are mutually exclusive, if you have
/dev/tty0? corresponding /dev/ttyd? must be removed and vice versa.
.Sh DIAGNOSTICS
.Bl -diag
.It sio%d: silo overflow.
The single-character input
.Dq silo
has overflowed and incoming data has been lost.
.\".It com%d: weird interrupt: %x.
.\"The device has generated an unexpected interrupt
.\"with the code listed.
Problem in the interrupt handler.
.El
.Bl -diag
.It sio%d: interrupt-level buffer overflow.
Problem in the bottom half of the driver.
.El
.Bl -diag
.It sio%d: tty-level buffer overflow.
Problem in the application.
.sp
Input has arrived faster than the given module could process it
and some has been lost.
.sp
.El
.Bl -diag
.It sio%d: reduced fifo trigger level to %d.
Attempting to avoid further silo overflows.
.Sh SEE ALSO
.Xr tty 4 ,
.Xr termios 4 ,
.Xr comcontrol 8 ,
.Xr stty 1 .
.Sh HISTORY
@ -180,12 +299,12 @@ driver is derived from the
driver and is
.Ud
.Sh BUGS
Data loss is not near as likely on busy systems as they are with the
Data loss is not nearly as likely on busy systems as it is with the
.Xr com 4
driver but they still can occur at very high baud rates on slow systems. The
use of NS16550A's helps lot to handle high baud rates.
driver but it can still occur at very high baud rates on slow systems.
The use of NS16550A's reduces system load and helps to avoid data loss.
.Pp
Stay away from NS16550 (so without the trailing A). These are early
Stay away from plain NS16550's. These are early
implementations of the chip with non-functional FIFO hardware.
.Pp
The constants which define the locations
@ -193,12 +312,13 @@ of the various serial ports are holdovers from
.Nm DOS .
As shown, hex addresses can be and for clarity probably should be used instead.
.Pp
As usual, you get what you pay for; cheap NS16550 clones generally don't work.
.Pp
The multiport example is based on an AST/4 card, your
mileage may vary however. Note that on the AST/4 the card's dipswitches should
Note that on the AST/4 the card's dipswitches should
.Nm not
be set to use interrupt sharing. AST/4-like interrupt sharing is only used when
be set to use interrupt sharing. AST/4-like interrupt sharing is only used when
.Nm multiple
AST/4 cards are installed in the same system. The sio driver does not
AST/4 cards are installed in the same system. The sio driver does not
support more than 1 AST/4 on one IRQ.
.Pp
Hardwired terminals should not have different device names.
.Pp
The examples in the synopsis are too vendor-specific.

274
share/man/man4/sio.4
View File

@ -36,7 +36,7 @@
.\" from: com.4,v 1.1 1993/08/06 11:19:07 cgd Exp
.\" $Id: sio.4,v 1.10 1994/05/07 01:15:10 ache Exp $
.\"
.Dd February 9, 1994
.Dd June 3, 1994
.Dt SIO 4 i386
.Os FreeBSD
.Sh NAME
@ -50,14 +50,42 @@ For standard ports:
.Cd "device sio2 at isa? port" \&"IO_COM3\&" tty irq 5 vector siointr
.Cd "device sio3 at isa? port" \&"IO_COM4\&" tty irq 9 vector siointr
.sp
For multiport cards:
For AST compatible multiport cards with 4 ports:
.Cd "options" \&"COM_MULTIPORT\&"
.Cd "device sio4 at isa? port 0x2a0 tty irq 12 flags 0x701 vector siointr"
.Cd "device sio5 at isa? port 0x2a8 tty flags 0x701 vector siointr"
.Cd "device sio6 at isa? port 0x2b0 tty flags 0x701 vector siointr"
.Cd "device sio7 at isa? port 0x2b8 tty flags 0x701 vector siointr"
.Cd "device sio4 at isa? port 0x2a0 tty flags 0x701"
.Cd "device sio5 at isa? port 0x2a8 tty flags 0x701"
.Cd "device sio6 at isa? port 0x2b0 tty flags 0x701"
.Cd "device sio7 at isa? port 0x2b8 tty flags 0x701 irq 12 vector siointr"
.sp
Use 0x02 bit in flags field to disable FIFO on specified port.
For Boca Board compatible multiport cards with 8 ports:
.Cd "options" \&"COM_MULTIPORT\&"
.Cd "device sio4 at isa? port 0x100 tty flags 0xb05"
.Cd "..."
.Cd "device sio11 at isa? port 0x138 tty flags 0xb05 irq 12 vector siointr"
.sp
Meaning of \fBflags\fR:
.br
\fB0x0001\fR shared IRQs
.br
\fB0x0002\fR disable FIFO
.br
\fB0x0004\fR no AST/4 compatible IRQ control register
.br
\fB0x0080\fR disable diagnostics in probe
.br
\fB0x\fI??\fB00\fR minor number of master port
.sp
Minor numbering:
.br
0b\fIOLIMMMMM\fR
.br
call\fBO\fRut
.br
\fBL\fRock
.br
\fBI\fRnitial
.br
\fBMMMMMM\fRinor
.Sh DESCRIPTION
The
.Nm sio
@ -67,108 +95,199 @@ driver provides support for NS8250-, NS16450-, NS16550 and NS16550A-based
.Pf ( Tn CCITT
.Tn V.24 )
communications interfaces. The NS8250 and NS16450 have single character
buffers, the NS16550A has a 16 character FIFO buffer.
buffers, the NS16550A has 16 character FIFO input and output buffers.
.Pp
Input and output for each line may set to one of following baud rates;
50, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600,
19200, 38400, 57600, or 115200. Your hardware may limit your baud
rate choices.
.Pp
The driver supports `multiport' cards.
The driver supports `multiport' cards.
Multiport cards are those that have one or more groups of ports
that share a common IRQ and Interrupt Request register set per group.
Frequently 4 ports share 1 IRQ, some 8 port cards have 2 groups of 4 ports,
that share an Interrupt Request (IRQ) line per group.
Shared IRQs on different cards are not supported.
Frequently 4 ports share 1 IRQ; some 8 port cards have 2 groups of 4 ports,
thus using 2 IRQs.
Some cards allow the first 2 serial ports to have seperate IRQs per port
(as per DOS PC standard).
.sp
Some cards have an IRQ control register for each group.
Some cards require special initialization related to such registers.
Only AST/4 compatible IRQ control registers are supported.
Some cards have an IRQ status register for each group.
The driver does not require or use such registers yet.
To work, the control and status registers for a group, if any,
must be mapped to the scratch register (register 7)
of a port in the group.
Such a port is called a
.Nm master
port.
.sp
The
.Nm flags
keyword specifies for each
keyword may be used on each
.Nm device sio
line in the kernel configuration file,
whether the port is part of an IRQ sharing group, & if so,
which port is the master device for
the group (ie which port has the IRQ control registers).
The master device is the port which
has registers through which all interrupts of the port group are funneled.
All ports of a port group report pending interrupts using this
single register.
line in the kernel configuration file
to silence the probe
or to disable the FIFO on 16550A UARTs
(see the synopsis).
Disabling the FIFO should rarely be necessary
since the driver automatically adjusts the receiver
FIFO trigger level for low latency and high efficiency.
.sp
The master device is an integer embedded in the high byte of the
The
.Nm flags
bitfield, so all sio entries in the kernel config file that are part of a
multiport card must include the correct
.Nm flags
specification.
The bitwise assignment allows multiple port groups to
be configured in one system. It does
keyword
.Nm must
be used for all ports that are part of an IRQ sharing group.
One bit specifies IRQ sharing; another bit specifies whether the port does
.Nm not
imply that more than one port group (or card) can share
the same physical interrupt line!
require AST/4 compatible initialization.
The minor number of the device corresponding a master port
for the group is encoded as a bitfield in the high byte.
The same master port must be specified for all ports in a group.
.sp
The
.Nm irq
and
.Nm vector
specifications must be given for master ports
and for ports that are not part of an IRQ sharing group,
and not for other ports.
.Pp
In the synopsis the
In the synopsis,
.Nm flags 0x701
means that the 8th port (sio7) is the master
device (so the MSB of the flags), and that the ports are part of a
multiport card (the LSB of the flags, actually only the LS
.Nm bit
).
F.e. if you have only two standard ports in addition to multiport
card, this
.Nm flags
will be
.Nm 0x501
(assuming the control port is
.Nm sio5
).
port, and that the port is on a multiport card with shared IRQs
and an AST/4 compatible IRQ control register.
.sp
.Nm flags 0xb05
means that the 12th port (sio11) is the master
port, and that the port is on a multiport card with shared IRQs
and no special IRQ control register.
.Pp
Which port is the master device depends on the card type. Consult
the hardware documentation of your card.
Which port is the master port depends on the card type.
Consult the hardware documentation of your card.
Since IRQ status registers are never used,
and IRQ control registers are only used for AST/4 compatible cards,
and some cards map the control/status registers to all ports in a group,
any port in a group will sometimes do for the master port.
Choose a port containing an IRQ status register for forwards compatibility,
and the highest possible port for consistency.
.Pp
Serial ports controlled by the
Serial ports controlled by the
.Nm sio
driver can be used for both dialin and dialout.
The minor number of the dialout
port is 128 higher than that of the corresponding dialin port. Use
.Xr stty 1
to enable or disable modem control as required by your setup.
driver can be used for both `callin' and `callout'.
For each port there is a callin device and a callout device.
The minor number of the callout device is 128 higher
than that of the corresponding callin port.
The callin device is general purpose.
Processes opening it normally wait for carrier
and for the callout device to become inactive.
The callout device is used to steal the port from
processes waiting for carrier on the callin device.
Processes opening it do not wait for carrier
and put any processes waiting for carrier on the callin device into
a deeper sleep so that they do not conflict with the callout session.
The callout device is abused for handling programs that are supposed
to work on general ports and need to open the port without waiting
but are too stupid to do so.
.Pp
While testing new cards & resolving card config DIP header &
.Nm sio flags
settings, to avoid coms. failure from lack of full modem DC level
settings on ports,
you are recommended to temporarily use syntax such as:
.Nm stty -f /dev/tty03 clocal
The
.Nm sio
driver also supports an initial-state and a lock-state control
device for each of the callin and the callout "data" devices.
The minor number of the initial-state device is 32 higher
than that of the corresponding data device.
The minor number of the lock-state device is 64 higher
than that of the corresponding data device.
The termios settings of a data device are copied
from those of the corresponding initial-state device
on first opens and are not inherited from previous opens.
Use
.Xr stty 1
in the normal way on the initial-state devices to program
initial termios states suitable for your setup.
.sp
The lock termios state acts as flags to disable changing
the termios state. E.g., to lock a flag variable such as
CRTSCTS, use
.Nm stty crtscts
on the lock-state device. Speeds and special characters
may be locked by setting the corresponding value in the lock-state
device to any nonzero value.
.sp
Correct programs talking to correctly wired external devices
work with arbitrary initial states and almost no locking,
but other setups may benefit from changing some of the default
initial state and locking the state.
E.g., CRTSCTS should be locked on for devices that support
RTS/CTS handshaking at all times and off for devices that don't
support it at all. CLOCAL should be locked on for devices
that don't support carrier. HUPCL may be locked off if you don't
want to hang up for reason. In general, very bad things happen
if something is locked to the wrong state, and things should not
be locked for devices that support more than one setting. The
CLOCAL flag on callin ports should be locked off for logins
to avoid certain security holes, but this needs to be done by
getty if the callin port is used for anything else.
.Sh FILES
.Bl -tag -width /dev/tty0? -compact
.Bl -tag -width /dev/ttyi0? -compact
.It Pa /dev/tty0?
for hardwired terminals
.It Pa /dev/ttyi0?
.It Pa /dev/ttyl0?
corresponding initial-state and lock-state devices
.El
.sp
or
.Bl -tag -width /dev/tty0? -compact
.sp
.Bl -tag -width /dev/ttyi0? -compact
.It Pa /dev/ttyd?
for dialin ports
for callin ports
.It Pa /dev/ttyid?
.It Pa /dev/ttyld?
corresponding callin initial-state and lock-state devices
.sp
.It Pa /dev/cua0?
for dialout ports
for callout ports
.It Pa /dev/cuai0?
.It Pa /dev/cual0?
corresponding callout initial-state and lock-state devices
.El
.sp
.Bl -tag -width /etc/rc.serial -compact
.It Pa /etc/rc.serial
examples of setting the initial-state and lock-state devices
.El
.Pp
The devices numbers are made from the set [0-9a-z] so that more than
The devices numbers are made from the set [0-9a-v] so that more than
10 ports can be supported.
/dev/tty0? and /dev/ttyd? are mutually exclusive, if you have
/dev/tty0? corresponding /dev/ttyd? must be removed and vice versa.
.Sh DIAGNOSTICS
.Bl -diag
.It sio%d: silo overflow.
The single-character input
.Dq silo
has overflowed and incoming data has been lost.
.\".It com%d: weird interrupt: %x.
.\"The device has generated an unexpected interrupt
.\"with the code listed.
Problem in the interrupt handler.
.El
.Bl -diag
.It sio%d: interrupt-level buffer overflow.
Problem in the bottom half of the driver.
.El
.Bl -diag
.It sio%d: tty-level buffer overflow.
Problem in the application.
.sp
Input has arrived faster than the given module could process it
and some has been lost.
.sp
.El
.Bl -diag
.It sio%d: reduced fifo trigger level to %d.
Attempting to avoid further silo overflows.
.Sh SEE ALSO
.Xr tty 4 ,
.Xr termios 4 ,
.Xr comcontrol 8 ,
.Xr stty 1 .
.Sh HISTORY
@ -180,12 +299,12 @@ driver is derived from the
driver and is
.Ud
.Sh BUGS
Data loss is not near as likely on busy systems as they are with the
Data loss is not nearly as likely on busy systems as it is with the
.Xr com 4
driver but they still can occur at very high baud rates on slow systems. The
use of NS16550A's helps lot to handle high baud rates.
driver but it can still occur at very high baud rates on slow systems.
The use of NS16550A's reduces system load and helps to avoid data loss.
.Pp
Stay away from NS16550 (so without the trailing A). These are early
Stay away from plain NS16550's. These are early
implementations of the chip with non-functional FIFO hardware.
.Pp
The constants which define the locations
@ -193,12 +312,13 @@ of the various serial ports are holdovers from
.Nm DOS .
As shown, hex addresses can be and for clarity probably should be used instead.
.Pp
As usual, you get what you pay for; cheap NS16550 clones generally don't work.
.Pp
The multiport example is based on an AST/4 card, your
mileage may vary however. Note that on the AST/4 the card's dipswitches should
Note that on the AST/4 the card's dipswitches should
.Nm not
be set to use interrupt sharing. AST/4-like interrupt sharing is only used when
be set to use interrupt sharing. AST/4-like interrupt sharing is only used when
.Nm multiple
AST/4 cards are installed in the same system. The sio driver does not
AST/4 cards are installed in the same system. The sio driver does not
support more than 1 AST/4 on one IRQ.
.Pp
Hardwired terminals should not have different device names.
.Pp
The examples in the synopsis are too vendor-specific.