From 7eda085c41faa3445b4b168ce78ab18dab87d98a Mon Sep 17 00:00:00 2001
From: Karel Zak
Date: Thu, 7 Dec 2006 00:25:39 +0100
Subject: Imported from util-linux-2.9v tarball.

---
 sys-utils/tunelp.8 | 135 ++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 102 insertions(+), 33 deletions(-)

(limited to 'sys-utils/tunelp.8')

diff --git a/sys-utils/tunelp.8 b/sys-utils/tunelp.8
index 8b148f20a..ac01ed400 100644
--- a/sys-utils/tunelp.8
+++ b/sys-utils/tunelp.8
@@ -1,32 +1,47 @@
 .\" This file Copyright (C) 1992-1997 Michael K. Johnson <johnsonm@redhat.com>
+.\" This file Copyright (C) 1998      Andrea Arcangeli   <andrea@e-mind.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"
+.\"
+.\" Polished a bit - aeb
+.TH tunelp 8 "7 May 1999" "tunelp" "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] ]
+\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] | - T [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
+without it...)  Without parameters, it tells whether the device is using
+interrupts, and if so, which one.  With parameters, it 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
+.TP
+.BI \-i " <IRQ>"
+specifies 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.
+The command
 .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.
+will probably be desirable.
 
--t \fI<TIME>\fP is the amount of time in jiffies that the driver waits if the
+NOTE: This option will have no effect with kernel 2.1.131 or later since
+the irq is handled by the parport driver. You can change
+the parport irq for example via
+.IR /proc/parport/*/irq .
+Read
+.I /usr/src/linux/Documentation/parport.txt
+for more details on parport.
+
+.TP
+.BI \-t " <TIME>"
+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
+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
@@ -34,51 +49,105 @@ 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
+.TP
+.BI \-c " <CHARS>"
+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.
+be a good value for most printers in polling mode.  1000 is the default,
+because there are some printers that become jerky otherwise, but you \fImust\fP
+set this to `1' to handle the maximal CPU efficiency if you are using
+interrupts. If you have a very fast printer, a value of 10 might make more
+sense even if in polling mode.
+If you have a \fIreally\fP old printer, you can increase this further.
 
-Setting -t \fI<TIME>\fP to 0 is equivalent to setting -c \fI<CHARS>\fP
+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.
+.TP
+.BI \-w " <WAIT>"
+is the number of usec we wait while playing with 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 1 may make it possible to print with those printers.  This may also
+make it possible to use longer cables. It's also possible to decrease this
+value to 0 if your printer is fast enough or your machine is slow enough.
 
--a [on|off] This is whether to abort on printer error -- the default
+.TP
+.B \-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
+.TP
+.B \-o [on|off]
+This option is much like \-a.  It makes any
+.I 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
+.TP
+.B \-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 
+NOTE: This option is obsolete because it's the default in 2.1.131 kernel
+or later.
+
+.TP
+.B \-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
+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.
+.TP
+.B \-T [on|off]
+This option tell the lp driver to trust or not the IRQ.
+This option makes sense only if you are using interrupts.
+If you tell the lp driver to trust the irq, then, when the lp driver will
+get an irq, it will send the next pending character to the printer
+unconditionally, even if the printer still claims to be BUSY.
+This is the only way to sleep on interrupt (and so the handle the irq
+printing efficiently) at least on Epson Stylus Color Printers.
+The lp driver automagically detects if you could get improved
+performance by setting this flag, and in such case it will warn you
+with a kernel message.
+
+NOTE: Trusting the irq is reported to corrupt the printing on some hardware,
+you must try to know if your printer will work or not...
 
--r This option resets the port.  It requires a Linux kernel version of
+.TP
+.B \-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.
+.TP
+.B \-q [on|off]
+This option sets printing the display of the current IRQ setting.
+
+
+.SH NOTES
+\-o, \-C, and \-s all require a Linux kernel version of 1.1.76 or later.
+
+\-C requires a Linux version prior to 2.1.131.
+
+\-T requires a Linux version of 2.1.131 or later.
+
+.SH BUGS
+By some unfortunate coincidence the ioctl LPSTRICT of 2.0.36 has the same
+number as the ioctl LPTRUSTIRQ introduced in 2.1.131. So, use of the \-T option
+on a 2.0.36 kernel with an tunelp compiled under 2.1.131 or later may have
+unexpected effects.
+
+.SH FILES
+.I /dev/lp?
+.br
+.I /proc/parport/*/*
-- 
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