99 lines
3.2 KiB
Groff
99 lines
3.2 KiB
Groff
.\" $NetBSD: boot_console.8,v 1.3 1998/02/25 12:30:13 drochner Exp $
|
|
.\"
|
|
.Dd September 30, 1997
|
|
.Os
|
|
.Dt BOOT_CONSOLE 8 i386
|
|
.Sh NAME
|
|
.Nm boot_console
|
|
.Nd selection of a console device in the i386 bootloader
|
|
|
|
.Sh DESCRIPTION
|
|
The i386 bootloader selects a console device for its user interaction
|
|
and passes information about it to the
|
|
.Nx
|
|
kernel. The selection process is controlled by bootloader compile-time
|
|
options and system setup at the bootloader startup time.
|
|
|
|
.Pp
|
|
The compile-time options (to set in the bootloader's
|
|
.Dq Makefile
|
|
) are:
|
|
.Bl -ohang
|
|
.It Cd SUPPORT_SERIAL
|
|
enables support for serial input / output. If not set, the standard PC
|
|
keyboard / display is always used as console device and the following
|
|
options are meaningless.
|
|
.It Cd DIRECT_SERIAL
|
|
causes direct hardware access to be used for serial input / output.
|
|
With this option, software handshake (XON/XOFF) is used for
|
|
flow control. Without this option, BIOS functions are employed for
|
|
serial port handling, which require hardware handshake lines to
|
|
be completely wired.
|
|
.It Cd CONSPEED=integer
|
|
sets the baudrate for the serial console. This option has only an
|
|
effect together with the
|
|
.Dq Cd DIRECT_SERIAL
|
|
option above. Otherwise, the default setting of 9600 baud is used.
|
|
.It Cd COMCONS_KEYPRESS
|
|
If console autoselection is used (see below), require a character
|
|
input within 1 second after a space character is sent to the serial
|
|
line for a serial console device to be selected. If not set, only a simple
|
|
function check is done (and the hardware handshake is checked
|
|
if
|
|
.Dq Cd DIRECT_SERIAL
|
|
is not defined).
|
|
.El
|
|
|
|
The actual policy for the console selection is determined by the
|
|
argument to the console initialization function
|
|
.Fn initio int
|
|
which is called early in the bootloader's
|
|
.Fn main
|
|
function. The following are available:
|
|
.Bl -ohang
|
|
.It Fa CONSDEV_PC
|
|
Use the standard PC keyboard / display as console.
|
|
.It Fa CONSDEV_COM0 Li ... Fa CONSDEV_COM3
|
|
Use the serial port with the corresponding BIOS number as
|
|
console. If the port is not known to the BIOS, it falls back to
|
|
.Dq Fa CONSDEV_PC
|
|
\& .
|
|
(Note1: This feature can be deliberately used for console
|
|
selection if the BIOS allows to disable serial ports.)
|
|
(Note2: This works with the
|
|
.Dq Cd DIRECT_SERIAL
|
|
option too.)
|
|
.It Fa CONSDEV_AUTO
|
|
Auto-select the console. First the serial ports known to the BIOS
|
|
are probed. If output of a (space) character to the port succeeds,
|
|
and the conditions described under
|
|
.Dq Cd COMCONS_KEYPRESS
|
|
above are fulfilled, the port is used as console. If no serial port
|
|
passes the check,
|
|
.Dq Fa CONSDEV_PC
|
|
is used. The progress of the selection process is shown at the PC display
|
|
as digits corresponding to the serial port number currently probed.
|
|
.El
|
|
|
|
.Sh FILES
|
|
.Bl -tag -width xxx
|
|
.It Pa /src/sys/arch/i386/stand/{bios,dos,net}boot/Makefile
|
|
.It Pa /src/sys/arch/i386/stand/{bios,dos,net}boot/main.c
|
|
.El
|
|
|
|
.Sh SEE ALSO
|
|
.Xr console 4 ,
|
|
.Xr boot 8
|
|
|
|
.Sh BUGS
|
|
There is generally no non-volatile storage available on the
|
|
PC platform. This requires autoselection methods which can
|
|
be inconvinient and / or unstable in some situations. The selection
|
|
policy should be adapted to the local hardware configuration, which
|
|
might require code changes.
|
|
.Pp
|
|
The serial communication parameters (bytesize, parity, stopbits)
|
|
are not setable. In any case,
|
|
.Dq 8N1
|
|
is used.
|