1.\"- 2.\" Copyright (c) 2001 Miodrag Vallat. 3.\" Copyright (c) 2005 Marius Strobl <marius@FreeBSD.org> 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistribution of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" 26.\" from: OpenBSD: pcons.4,v 1.4 2003/06/02 16:16:26 miod Exp 27.\" $FreeBSD$ 28.\" 29.Dd January 16, 2021 30.Dt OFW_CONSOLE 4 powerpc 31.Os 32.Sh NAME 33.Nm ofw_console 34.Nd "Open Firmware console" 35.Sh SYNOPSIS 36.Cd "cpu AIM" 37.Cd "options OFWCONS_POLL_HZ=N" 38.Pp 39.Cd "options KDB" 40.Cd "options DDB" 41.Cd "options ALT_BREAK_TO_DEBUGGER" 42.Sh DESCRIPTION 43The 44.Nm 45driver provides a simple text console, 46using the Open Firmware services for input and output. 47It will use the Open Firmware console devices set via the 48.Va input-device 49and 50.Va output-device 51variables. 52.Pp 53This driver is deprecated and only provided as a fallback console mechanism 54if the real console hardware can not be driven by 55.Fx . 56.Pp 57In case the 58.Nm 59console appears to work too slowly, its responsiveness probably can be improved 60by including 61.Cd "options OFWCONS_POLL_HZ=N" . 62When omitted, 63.Dv OFWCONS_POLL_HZ 64defaults to 4. 65For example, on 66.Tn Sun Ultra 2 67a value of 20 or higher works best. 68Too high values, on the other hand, can cause 69.Nm 70to unnecessarily consume CPU. 71.Sh FILES 72.Bl -tag -width ".Pa /dev/keyboard" -compact 73.It Pa /dev/console 74.It Pa /dev/keyboard 75terminal input device in case the console input device is the keyboard 76.It Pa /dev/screen 77terminal output device in case the console output device is the screen 78.It Pa /dev/tty[a-z] 79terminal device in case both the console input and output device is tty[a-z] 80.El 81.Sh SEE ALSO 82.Xr akbd 4 , 83.Xr powermac_nvram 4 , 84.Xr vt 4 85.Sh HISTORY 86The 87.Nm 88driver first appeared in 89.Fx 5.0 . 90.Sh AUTHORS 91The 92.Nm 93driver was written by 94.An Benno Rice Aq Mt benno@FreeBSD.org . 95.Sh CAVEATS 96Since the Open Firmware will handle BREAK 97(or Stop-A) 98sequences before 99.Nm , 100the preferred way to enter 101.Xr ddb 4 102when using 103.Nm 104is to include 105.Cd "options ALT_BREAK_TO_DEBUGGER" 106in a ddb-enabled kernel, and enter the alternate BREAK sequence 107(RETURN TILDE CTRL-b). 108.Sh BUGS 109The 110.Nm 111driver also not attach to the hardware resources it actually talks to. 112