.\" Copyright (c) 2003 Hidetoshi Shimokawa
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" $FreeBSD$
.\"
.Dd January 26, 2008
.Dt DCONS 4
.Os
.Sh NAME
.Nm dcons
.Nd dumb console device driver
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your kernel configuration file:
.Bd -ragged -offset indent
.Cd "options GDB"
.Cd "device firewire"
.Cd "device dcons"
.Ed
.Pp
Alternatively, to load the driver as a module at boot time,
place the following line in your kernel configuration file:
.Bd -ragged -offset indent
.Cd "options GDB"
.Ed
.Pp
and in
.Xr loader.conf 5 :
.Bd -ragged -offset indent
dcons_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
device is a simple console device which just reads from and writes to
an allocated buffer for input and output respectively.
It is of no use by itself and it is supposed that the buffer is accessed
via a bus like
.Xr firewire 4
or
.Xr kvm 3
for interaction.
.Pp
The buffer consists of 4 channels.
There are 2 ports, one for the console TTY and another is GDB port,
then each port has an input channel and an output channel.
.Sh FILES
.Bl -tag -width indent -compact
.It Pa /dev/dcons
.It Pa /etc/ttys
.El
.Sh EXAMPLES
If you want to run
.Xr getty 8
on
.Nm ,
insert the following line into
.Xr ttys 5
and send a
.Dv HUP
signal to
.Xr init 8
using
.Xr kill 1 .
.Bd -literal -offset indent
dcons	"/usr/libexec/getty std.9600"	vt100	on  secure
.Ed
.Pp
Once the
.Xr fwohci 4
device is initialized to allow physical access,
the buffer can be accessed from another host via a
.Xr firewire 4
bus using the
.Xr dconschat 8
application.
See
.Xr dconschat 8
for more details.
.Pp
If you want to use
.Nm
as a
.Xr gdb 1 Pq Pa ports/devel/gdb
port, add the following line into
.Xr loader.conf 5 :
.Bd -literal -offset indent
dcons_gdb="1"
.Ed
.Sh SEE ALSO
.Xr dcons_crom 4 ,
.Xr ddb 4 ,
.Xr firewire 4 ,
.Xr fwohci 4 ,
.Xr gdb 4 ,
.Xr ttys 5 ,
.Xr conscontrol 8 ,
.Xr dconschat 8 ,
.Xr fwcontrol 8
.Sh AUTHORS
.An Hidetoshi Shimokawa Aq Mt simokawa@FreeBSD.org
.Sh BUGS
This driver is
.Ud