1.\" 2.\" Copyright (c) 1993 Christopher G. Demetriou 3.\" Copyright (c) 1994 Geoffrey M. Rehmet 4.\" Copyright (c) 1999 Nicolas Souchu 5.\" All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $FreeBSD: src/share/man/man4/lpt.4,v 1.9.2.2 2001/08/17 13:08:38 ru Exp $ 29.\" $DragonFly: src/share/man/man4/lpt.4,v 1.3 2006/02/17 19:37:09 swildner Exp $ 30.\" 31.Dd February 14, 1999 32.Dt LPT 4 33.Os 34.Sh NAME 35.Nm lpt 36.Nd generic printer device driver 37.Sh SYNOPSIS 38.Cd "device ppbus" 39.Cd "device lpt" 40.Pp 41.Cd "device ppc0 at isa? port IO_LPT1 irq 7" 42.Cd "device ppc1 at isa? port IO_LPT2 irq 7" 43.Cd "device ppc2 at isa? port IO_LPT3 irq 7" 44.Pp 45For BIOS-probed ports: 46.Cd "device ppc0 at isa? port? irq 7" 47.Pp 48For polled ports: 49.Cd "device ppc0 at isa? port?" 50.Cd "device ppc1 at isa? port IO_LPT2" 51.Pp 52For DMA capable parallel port: 53.Cd "device ppc0 at isa? port? irq 7 drq 1" 54.Sh DESCRIPTION 55The current 56.Em lpt 57driver is the port of the original lpt driver to the 58.Xr ppbus 4 59system. 60.Pp 61One purpose of this port was to allow parallel port sharing with other 62parallel devices. 63Secondly, 64.Fn inb / outb 65calls have been replaced by ppbus function calls. 66lpt is now arch-independent thanks to the ppbus interface. 67See 68.Xr ppbus 4 69for more info about the ppbus system. 70.Pp 71The parallel port bus is allocated by lpt when the printer device is opened 72and released only when the transfer is completed: either when the device 73is closed or when the entire buffer is sent in interrupt driven mode. 74.Pp 75The driver can be configured to be either interrupt-driven, or 76to poll the printer. Ports that are configured to be 77interrupt-driven can be switched to polled mode by using the 78.Xr lptcontrol 8 79command. 80.Pp 81Depending on your hardware, extended capabilities may be configured with the 82.Xr lptcontrol 8 83command. 84With an ECP/ISA port, you can take advantage 85of FIFO and DMA. 86.Pp 87In order to retrieve printer info from /dev/lpt0, just apply the 88.Nm cat 89command to the device. 90If the printer supports IEEE1284 nibble mode and has 91data to send to the host, you'll get it. 92.Sh FILES 93.Bl -tag -width Pa -compact 94.It Pa /dev/lpt0 95first parallel port driver 96.El 97.Sh SEE ALSO 98.Xr ppbus 4 , 99.Xr lptcontrol 8 100.Sh HISTORY 101This driver replaces the functionality of the lpa 102driver, which is now defunct. 103.Sh BUGS 104There are lots of them, especially in cheap parallel port implementations. 105.Pp 106It is only possible to open a lpt port when a printer is connected and 107on-line, making it impossible to run 108.Xr lptcontrol 8 109when there is no printer connected. 110.Pp 111This driver could still stand a rewrite. 112