| '\" t |
| .\" Copyright (c) Michael Haardt (michael@cantor.informatik.rwth-aachen.de), |
| .\" Sun Jan 15 19:16:33 1995 |
| .\" |
| .\" %%%LICENSE_START(GPLv2+_DOC_FULL) |
| .\" This is free documentation; you can redistribute it and/or |
| .\" modify it under the terms of the GNU General Public License as |
| .\" published by the Free Software Foundation; either version 2 of |
| .\" the License, or (at your option) any later version. |
| .\" |
| .\" The GNU General Public License's references to "object code" |
| .\" and "executables" are to be interpreted as the output of any |
| .\" document formatting or typesetting system, including |
| .\" intermediate and printed output. |
| .\" |
| .\" This manual is distributed in the hope that it will be useful, |
| .\" but WITHOUT ANY WARRANTY; without even the implied warranty of |
| .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| .\" GNU General Public License for more details. |
| .\" |
| .\" You should have received a copy of the GNU General Public |
| .\" License along with this manual; if not, see |
| .\" <http://www.gnu.org/licenses/>. |
| .\" %%%LICENSE_END |
| .\" |
| .\" Modified, Sun Feb 26 15:02:58 1995, faith@cs.unc.edu |
| .TH LP 4 1995-01-15 "Linux" "Linux Programmer's Manual" |
| .SH NAME |
| lp \- line printer devices |
| .SH SYNOPSIS |
| .B #include <linux/lp.h> |
| .SH CONFIGURATION |
| \fBlp\fP[0\(en2] are character devices for the parallel line printers; |
| they have major number 6 and minor number 0\(en2. |
| The minor numbers |
| correspond to the printer port base addresses 0x03bc, 0x0378 and 0x0278. |
| Usually they have mode 220 and are owned by root and group lp. |
| You can use printer ports either with polling or with interrupts. |
| Interrupts are recommended when high traffic is expected, for example, |
| for laser printers. |
| For typical dot matrix printers, polling will usually be enough. |
| The default is polling. |
| .SH DESCRIPTION |
| The following |
| .BR ioctl (2) |
| calls are supported: |
| .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPTIME, int \fP\fIarg\fP\fB)\fP" |
| Sets the amount of time that the driver sleeps before rechecking the printer |
| when the printer's buffer appears to be filled to |
| .IR arg . |
| If you have a fast printer, decrease this number; |
| if you have a slow printer, then increase it. |
| This is in hundredths of a second, the default 2 |
| being 0.02 seconds. |
| It only influences the polling driver. |
| .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPCHAR, int \fP\fIarg\fP\fB)\fP" |
| Sets the maximum number of busy-wait iterations which the polling driver does |
| while waiting for the printer to get ready for receiving a character to |
| .IR arg . |
| If printing is too slow, increase this number; if the |
| system gets too slow, decrease this number. |
| The default is 1000. |
| It only influences the polling driver. |
| .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPABORT, int \fP\fIarg\fP\fB)\fP" |
| If |
| .I arg |
| is 0, the printer driver will retry on errors, otherwise |
| it will abort. |
| The default is 0. |
| .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPABORTOPEN, int \fP\fIarg\fP\fB)\fP" |
| If |
| .I arg |
| is 0, |
| .BR open (2) |
| will be aborted on error, otherwise error will be ignored. |
| The default is to ignore it. |
| .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPCAREFUL, int \fP\fIarg\fP\fB)\fP" |
| If |
| .I arg |
| is 0, then the out-of-paper, offline and error signals are |
| required to be false on all writes, otherwise they are ignored. |
| The default is to ignore them. |
| .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPWAIT, int \fP\fIarg\fP\fB)\fP" |
| Sets the number of busy waiting iterations to wait before strobing the |
| printer to accept a just-written character, and the number of iterations to |
| wait before turning the strobe off again, |
| to |
| .IR arg . |
| The specification says this time should be 0.5 |
| microseconds, but experience has shown the delay caused by the code is |
| already enough. |
| For that reason, the default value is 0. |
| This is used for both the polling and the interrupt driver. |
| .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPSETIRQ, int \fP\fIarg\fP\fB)\fP" |
| This |
| .BR ioctl (2) |
| requires superuser privileges. |
| It takes an |
| .I int |
| containing the new IRQ as argument. |
| As a side effect, the printer will be reset. |
| When |
| .I arg |
| is 0, the polling driver will be used, which is also default. |
| .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPGETIRQ, int *\fP\fIarg\fP\fB)\fP" |
| Stores the currently used IRQ in |
| .IR arg . |
| .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPGETSTATUS, int *\fP\fIarg\fP\fB)\fP" |
| Stores the value of the status port in |
| .IR arg . |
| The bits have the following meaning: |
| .TS |
| l l. |
| LP_PBUSY inverted busy input, active high |
| LP_PACK unchanged acknowledge input, active low |
| LP_POUTPA unchanged out-of-paper input, active high |
| LP_PSELECD unchanged selected input, active high |
| LP_PERRORP unchanged error input, active low |
| .TE |
| .sp |
| Refer to your printer manual for the meaning of the signals. |
| Note that undocumented bits may also be set, depending on your printer. |
| .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPRESET)\fP" |
| Resets the printer. |
| No argument is used. |
| .SH FILES |
| /dev/lp* |
| .\" .SH AUTHORS |
| .\" The printer driver was originally written by Jim Weigand and Linus |
| .\" Torvalds. |
| .\" It was further improved by Michael K.\& Johnson. |
| .\" The interrupt code was written by Nigel Gamble. |
| .\" Alan Cox modularized it. |
| .\" LPCAREFUL, LPABORT, LPGETSTATUS were added by Chris Metcalf. |
| .SH SEE ALSO |
| .BR chmod (1), |
| .BR chown (1), |
| .BR mknod (1), |
| .BR lpcntl (8), |
| .BR tunelp (8) |