CONS(4) | Device Drivers Manual (x86) | CONS(4) |
console
— x86
console interface
options CONSDEVNAME=string
options CONADDR=integer
options CONSPEED=integer
options CONS_OVERRIDE
options CONMODE=integer
The “console” device is used for kernel printf messages and accesses to the /dev/console character special device in user mode. It is attached to a hardware interface at boot time controlled by options in the kernel configuration file, or information passed by the boot loader.
Bootblocks from NetBSD 1.4 or newer select their console device from a compiled-in list, and then pass their choice of console device and console parameters to the kernel.
As of NetBSD 1.5, the
consdev
bootblock command allows changing the
console device on-the-fly.
The kernel will use the same console device as the bootblock; no special kernel configuration is required.
To override the bootblock's choice of console, or to use a serial kernel console with older bootblocks, you must specify kernel config-file options to override the information passed by the bootblock. The current option choices are:
The available kernel configuration options are:
options CONSDEVNAME=string
options CONADDR=integer
options CONSPEED=integer
options CONS_OVERRIDE
options CONMODE=integer
CREAD
|
CS8
|
HUPCL
)
(8N1). This option takes always effect, because mode settings are not
passed by the bootloader.options
CONSDEVNAME="\"com\"",CONADDR=0x2f8,CONSPEED=57600
The console device is chosen early in system startup regardless if
the specified driver / device is present in the system configuration file.
If the driver asked for by the bootloader or
“options CONSDEVNAME
” is not
configured into the system, a panic is caused. Because there is no console
device, no explaining message will be printed. If the driver is present, but
the specific device instance not, kernel printf will work, but
/dev/console becomes a dummy.
September 6, 2006 | NetBSD 10.99 |