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OFW_CONSOLE(4) FreeBSD Kernel Interfaces Manual (powerpc) OFW_CONSOLE(4)
NAME
ofw_console - Open Firmware console
SYNOPSIS
cpu AIM
options OFWCONS_POLL_HZ=N
options KDB
options DDB
options ALT_BREAK_TO_DEBUGGER
DESCRIPTION
The ofw_console driver provides a simple text console, using the Open
Firmware services for input and output. It will use the Open Firmware
console devices set via the input-device and output-device variables.
This driver is deprecated and only provided as a fallback console
mechanism if the real console hardware can not be driven by FreeBSD.
In case the ofw_console console appears to work too slowly, its
responsiveness probably can be improved by including options
OFWCONS_POLL_HZ=N. When omitted, OFWCONS_POLL_HZ defaults to 4. For
example, on Sun Ultra 2 a value of 20 or higher works best. Too high
values, on the other hand, can cause ofw_console to unnecessarily consume
CPU.
FILES
/dev/console
/dev/keyboard terminal input device in case the console input device is
the keyboard
/dev/screen terminal output device in case the console output device
is the screen
/dev/tty[a-z] terminal device in case both the console input and output
device is tty[a-z]
SEE ALSO
akbd(4), powermac_nvram(4), vt(4)
HISTORY
The ofw_console driver first appeared in FreeBSD 5.0.
AUTHORS
The ofw_console driver was written by Benno Rice <benno@FreeBSD.org>.
CAVEATS
Since the Open Firmware will handle BREAK (or Stop-A) sequences before
ofw_console, the preferred way to enter ddb(4) when using ofw_console is
to include options ALT_BREAK_TO_DEBUGGER in a ddb-enabled kernel, and
enter the alternate BREAK sequence (RETURN TILDE CTRL-b).
BUGS
The ofw_console driver also not attach to the hardware resources it
actually talks to.
FreeBSD 14.0-RELEASE-p11 January 16, 2021 FreeBSD 14.0-RELEASE-p11