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.\" 28.Dd January 16, 2021 29.Dt OFW_CONSOLE 4 powerpc 30.Os 31.Sh NAME 32.Nm ofw_console 33.Nd "Open Firmware console" 34.Sh SYNOPSIS 35.Cd "cpu AIM" 36.Cd "options OFWCONS_POLL_HZ=N" 37.Pp 38.Cd "options KDB" 39.Cd "options DDB" 40.Cd "options ALT_BREAK_TO_DEBUGGER" 41.Sh DESCRIPTION 42The 43.Nm 44driver provides a simple text console, 45using the Open Firmware services for input and output. 46It will use the Open Firmware console devices set via the 47.Va input-device 48and 49.Va output-device 50variables. 51.Pp 52This driver is deprecated and only provided as a fallback console mechanism 53if the real console hardware can not be driven by 54.Fx . 55.Pp 56In case the 57.Nm 58console appears to work too slowly, its responsiveness probably can be improved 59by including 60.Cd "options OFWCONS_POLL_HZ=N" . 61When omitted, 62.Dv OFWCONS_POLL_HZ 63defaults to 4. 64For example, on 65.Tn Sun Ultra 2 66a value of 20 or higher works best. 67Too high values, on the other hand, can cause 68.Nm 69to unnecessarily consume CPU. 70.Sh FILES 71.Bl -tag -width ".Pa /dev/keyboard" -compact 72.It Pa /dev/console 73.It Pa /dev/keyboard 74terminal input device in case the console input device is the keyboard 75.It Pa /dev/screen 76terminal output device in case the console output device is the screen 77.It Pa /dev/tty[a-z] 78terminal device in case both the console input and output device is tty[a-z] 79.El 80.Sh SEE ALSO 81.Xr akbd 4 , 82.Xr powermac_nvram 4 , 83.Xr vt 4 84.Sh HISTORY 85The 86.Nm 87driver first appeared in 88.Fx 5.0 . 89.Sh AUTHORS 90The 91.Nm 92driver was written by 93.An Benno Rice Aq Mt benno@FreeBSD.org . 94.Sh CAVEATS 95Since the Open Firmware will handle BREAK 96(or Stop-A) 97sequences before 98.Nm , 99the preferred way to enter 100.Xr ddb 4 101when using 102.Nm 103is to include 104.Cd "options ALT_BREAK_TO_DEBUGGER" 105in a ddb-enabled kernel, and enter the alternate BREAK sequence 106(RETURN TILDE CTRL-b). 107.Sh BUGS 108The 109.Nm 110driver also not attach to the hardware resources it actually talks to. 111