BOOT_CONSOLE(8) | System Manager's Manual (x86) | BOOT_CONSOLE(8) |
boot_console
—
selection of a console device in the x86
bootloader
The NetBSD x86 bootloader selects a console device for its user interaction and passes information about it to the NetBSD kernel. When booting from the system BIOS, the console device and properties are saved in the primary bootstrap by installboot(8). For other boot procedures (such as 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.
The compile-time options (to be set in the booter's “Makefile”) are:
DIRECT_SERIAL
” option above,
otherwise, the default setting of 9600 baud is used. The value of
integer must be something that makes sense as a
serial port baud rate.The actual policy for the console selection is determined by the
value of “SUPPORT_SERIAL
” The
following options are available:
...
CONSDEV_COM3CONSDEV_PC
”. (Note: This feature
can be deliberately used for console selection if the serial ports have
been disabled in the BIOS.)...
CONSDEV_COM3KBDDIRECT_SERIAL
” is
defined the RS-232 “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
“CONSDEV_PC
”.DIRECT_SERIAL
” is defined the
RS-232 “modem ready” status is on after the character is
output), the port is used as console. If no serial port passes the check,
“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.The serial communication parameters (byte-size, parity, stop-bits) are not settable (either at compile time or run time). The default parameters are “8 N 1”.
The baud rate is not settable when using BIOS I/O. It should be
settable at compile time with
“CONSPEED
” just as it is when using
“DIRECT_SERIAL
”. The default speed is
9600 baud (the maximum for BIOS I/O).
February 17, 2017 | NetBSD 10.99 |