| .\" This file Copyright (C) 1992-1997 Michael K. Johnson <johnsonm@redhat.com> |
| .\" It may be distributed under the terms of the GNU General Public License, |
| .\" version 2, or any higher version. See section COPYING of the GNU General |
| .\" Public license for conditions under which this file may be redistributed. |
| .\" $Id: tunelp.8,v 1.6 1997/06/20 16:10:35 janl Exp $ |
| .TH tunelp 8 "26 August 1992" "Cohesive Systems" "Linux Programmer's Manual" |
| .SH NAME |
| tunelp \- set various parameters for the lp device |
| .SH SYNOPSIS |
| \fBtunelp\fP \fI<device>\fP [-i \fI<IRQ>\fP | -t \fI<TIME>\fP | -c \fI<CHARS>\fP | -w \fI<WAIT>\fP | -a [on|off] | -o [on|off] | -C [on|off] | -r | -s | -q [on|off] ] |
| .SH DESCRIPTION |
| \fBtunelp\fP sets several parameters for the /dev/lp\fI?\fP devices, for better |
| performance (or for any performance at all, if your printer won't work |
| without it...) Without parameters, tells whether the device is using |
| interrups, and if so, which one. With parameters, sets the device |
| characteristics accordingly. The parameters are as follows: |
| |
| -i \fI<IRQ>\fP is the IRQ to use for the parallel port in question. If this |
| is set to something non-zero, -t and -c have no effect. If your port |
| does not use interrupts, this option will make printing stop. |
| .B tunelp -i 0 |
| restores non-interrupt driven (polling) action, and your printer should |
| work again. If your parallel port does support interrupts, |
| interrupt-driven printing should be somewhat faster and efficient, and |
| will probably be desireable. |
| |
| -t \fI<TIME>\fP is the amount of time in jiffies that the driver waits if the |
| printer doesn't take a character for the number of tries dictated by |
| the -c parameter. 10 is the default value. If you want fastest |
| possible printing, and don't care about system load, you may set this |
| to 0. If you don't care how fast your printer goes, or are printing |
| text on a slow printer with a buffer, then 500 (5 seconds) should be |
| fine, and will give you very low system load. This value generally |
| should be lower for printing graphics than text, by a factor of |
| approximately 10, for best performance. |
| |
| -c \fI<CHARS>\fP is the number of times to try to output a character to the |
| printer before sleeping for -t \fI<TIME>\fP. It is the number of times around |
| a loop that tries to send a character to the printer. 120 appears to |
| be a good value for most printers. 250 is the default, because there |
| are some printers that require a wait this long, but feel free to |
| change this. If you have a very fast printer like an HP laserjet 4, a |
| value of 10 might make more sense. If you have a \fIreally\fP old |
| printer, you can increase this farther. |
| |
| Setting -t \fI<TIME>\fP to 0 is equivalent to setting -c \fI<CHARS>\fP |
| to infinity. |
| |
| -w \fI<WAIT>\fP is the a busy loop counter for the strobe signal. While most |
| printers appear to be able to deal with an extremely short strobe, |
| some printers demand a longer one. Increasing this from the default |
| 0 may make it possible to print with those printers. This may also |
| make it possible to use longer cables. |
| |
| -a [on|off] This is whether to abort on printer error -- the default |
| is not to. If you are sitting at your computer, you probably want to |
| be able to see an error and fix it, and have the printer go on |
| printing. On the other hand, if you aren't, you might rather that |
| your printer spooler find out that the printer isn't ready, quit |
| trying, and send you mail about it. The choice is yours. |
| |
| -o [on|off] This option is much like -a. It makes any open() of this |
| device check to see that the device is on-line and not reporting any |
| out of paper or other errors. This is the correct setting for most |
| versions of lpd. |
| |
| -C [on|off] This option adds extra ("careful") error checking. When |
| this option is on, the printer driver will ensure that the printer is |
| on-line and not reporting any out of paper or other errors before |
| sending data. This is particularly useful for printers that normally |
| appear to accept data when turned off. |
| |
| -s This option returns the current printer status, both as a |
| decimal number from 0..255, and as a list of active flags. When |
| this option is specified, -q off, turning off the display of the |
| current IRQ, is implied. |
| |
| -o, -C, and -s all require a Linux kernel version of 1.1.76 or later. |
| |
| -r This option resets the port. It requires a Linux kernel version of |
| 1.1.80 or later. |
| |
| -q [on|off] This option sets printing the display of the current IRQ |
| setting. |