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.\" $FreeBSD$ 29.\" 30.Dd February 14, 1999 31.Dt LPT 4 32.Os 33.Sh NAME 34.Nm lpt 35.Nd generic printer device driver 36.Sh SYNOPSIS 37.Cd "device ppc" 38.Cd "device ppbus" 39.Cd "device lpt" 40.Sh DESCRIPTION 41The current 42.Em lpt 43driver is the port of the original lpt driver to the 44.Xr ppbus 4 45system. 46.Pp 47One purpose of this port was to allow parallel port sharing with other 48parallel devices. 49Secondly, inb()/outb() calls have been replaced by ppbus 50function calls. 51lpt is now arch-independent thanks to the ppbus interface. 52See 53.Xr ppbus 4 54for more info about the ppbus system. 55.Pp 56The parallel port bus is allocated by lpt when the printer device is opened 57and released only when the transfer is completed: either when the device 58is closed or when the entire buffer is sent in interrupt driven mode. 59.Pp 60The driver can be configured to be either interrupt-driven, or 61to poll the printer. 62Ports that are configured to be 63interrupt-driven can be switched to polled mode by using the 64.Xr lptcontrol 8 65command. 66.Pp 67Depending on your hardware, extended capabilities may be configured with the 68.Xr lptcontrol 8 69command. 70With an ECP/ISA port, you can take advantage 71of FIFO and DMA. 72.Pp 73In order to retrieve printer info from /dev/lpt0, just apply the 74.Nm cat 75command to the device. 76If the printer supports IEEE1284 nibble mode and has 77data to send to the host, you will get it. 78.Sh FILES 79.Bl -tag -width Pa -compact 80.It Pa /dev/lpt0 81first parallel port driver 82.El 83.Sh SEE ALSO 84.Xr ppbus 4 , 85.Xr ppc 4 , 86.Xr lptcontrol 8 87.Sh HISTORY 88This driver replaces the functionality of the lpa 89driver, which is now defunct. 90.Sh BUGS 91There are lots of them, especially in cheap parallel port implementations. 92.Pp 93It is only possible to open a lpt port when a printer is connected and 94on-line, making it impossible to run 95.Xr lptcontrol 8 96when there is no printer connected. 97.Pp 98This driver could still stand a rewrite. 99