.\" $NetBSD: boot_console.8,v 1.4 2017/02/18 21:39:53 wiz Exp $ .\" .\" Copyright (c) 1997 .\" Matthias Drochner. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd February 17, 2017 .Dt BOOT_CONSOLE 8 x86 .Os .Sh NAME .Nm boot_console .Nd selection of a console device in the x86 bootloader .\" .Sh DESCRIPTION The .Nx x86 bootloader selects a console device for its user interaction and passes information about it to the .Nx kernel. When booting from the system BIOS, the console device and properties are saved in the primary bootstrap by .Xr installboot 8 . For other boot procedures (such as .Xr x86/dosboot 8 ) the selection process is controlled by bootloader compile-time options and system setup at the bootloader startup time. The selection may be changed on-the-fly from within the bootloader. .\" .Ss Serial Console Options The compile-time options (to be set in the booter's .Dq Makefile ) are: .Bl -ohang .It Sy SUPPORT_SERIAL= Ns Fa policy enables support for serial input/output. By default this option is not set and the standard PC keyboard and display are always used as the console device. See .Sx Console Selection Policy below for valid values of .Fa policy . .It Sy 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 Sy CONSPEED= Ns Fa integer sets the baud-rate for the serial console. This option has only an effect when used in combination with the .Dq Dv DIRECT_SERIAL option above, otherwise, the default setting of 9600 baud is used. The value of .Fa integer must be something that makes sense as a serial port baud rate. .It Sy COMCONS_KEYPRESS Require a character input within seven (7) seconds from serial console device to be selected. .El .\" .Ss Console Selection Policy The actual policy for the console selection is determined by the value of .Dq Dv SUPPORT_SERIAL The following options are available: .Bl -ohang .It Em CONSDEV_PC Force use of the standard PC keyboard and display as the console. .It Em CONSDEV_COM0 Li ... Em CONSDEV_COM3 Use the serial port with the corresponding BIOS number as the console. No attempt is made to verify connectivity on the selected port. If the port is not known to the BIOS, it falls back to .Dq Dv CONSDEV_PC . (Note: This feature can be deliberately used for console selection if the serial ports have been disabled in the BIOS.) .It Em CONSDEV_COM0KBD Li ... Em CONSDEV_COM3KBD If the port is known to the BIOS, and output of a character to the port succeeds (and if .Dq Dv DIRECT_SERIAL is defined the RS-232 .Dq "modem ready" status is on after the character is output), the port is used as console. If the port is not known to the BIOS, or the test output fails, it falls back to .Dq Dv CONSDEV_PC . .It Em CONSDEV_AUTO Auto-select the console. All serial ports known to the BIOS are probed in sequence. If output of a character to the port succeeds (and if .Dq Dv DIRECT_SERIAL is defined the RS-232 .Dq "modem ready" status is on after the character is output), the port is used as console. If no serial port passes the check, .Dq Dv 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 src/sys/arch/i386/stand/{boot,pxeboot}/Makefile .It Pa src/sys/arch/i386/stand/{boot,pxeboot}/Makefile compile time options for the boot programs. .El .\" .Sh SEE ALSO .Xr console 4 , .Xr installboot 8 , .Xr x86/boot 8 .\" .Sh BUGS The serial communication parameters (byte-size, parity, stop-bits) are not settable (either at compile time or run time). The default parameters are .Dq "8 N 1" . .Pp The baud rate is not settable when using BIOS I/O. It should be settable at compile time with .Dq Dv CONSPEED just as it is when using .Dq Dv DIRECT_SERIAL . The default speed is 9600 baud (the maximum for BIOS I/O).