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of this port was to allow parallel port sharing with other 46parallel devices. 47Secondly, inb()/outb() calls have been replaced by ppbus 48function calls. 49lpt is now arch-independent thanks to the ppbus interface. 50See 51.Xr ppbus 4 52for more info about the ppbus system. 53.Pp 54The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