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DCONS(4) Device Drivers Manual DCONS(4)

NAME

dcons —
dumb console device driver

SYNOPSIS

To compile this driver into the kernel, place the following lines in your kernel configuration file:
options GDB
device firewire
device dcons

Alternatively, to load the driver as a module at boot time, place the following line in your kernel configuration file:

options GDB

and in loader.conf(5):

dcons_load="YES"

DESCRIPTION

The dcons 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 firewire(4) or kvm(3) for interaction.

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.

FILES

/dev/dcons
 
/etc/ttys
 

EXAMPLES

If you want to run getty(8) on dcons, insert the following line into ttys(5) and send a HUP signal to init(8) using kill(1). 
dcons	"/usr/libexec/getty std.9600"	vt100	on  secure

Once the fwohci(4) device is initialized to allow physical access, the buffer can be accessed from another host via a firewire(4) bus using the dconschat(8) application. See dconschat(8) for more details.

If you want to use dcons as a gdb(1) port, add the following line into loader.conf(5):

dcons_gdb="1"

SEE ALSO

dcons_crom(4), ddb(4), firewire(4), fwohci(4), gdb(4), ttys(5), conscontrol(8), dconschat(8), fwcontrol(8)

AUTHORS

Hidetoshi Shimokawa <simokawa@FreeBSD.org>

BUGS

This driver is currently under development.
January 26, 2008 Linux 4.19.0-10-amd64