147 lines
6.6 KiB
Groff
147 lines
6.6 KiB
Groff
.\" Copyright (C) 1992-1997 Michael K. Johnson <johnsonm@redhat.com>
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.\" Copyright (C) 1998 Andrea Arcangeli <andrea@e-mind.com>
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.\" It may be distributed under the terms of the GNU General Public License,
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.\" version 2, or any higher version. See section COPYING of the GNU General
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.\" Public license for conditions under which this file may be redistributed.
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.\"
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.TH TUNELP 8 "October 2011" "util-linux" "System Administration"
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.SH NAME
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tunelp \- set various parameters for the lp device
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.SH SYNOPSIS
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.B tunelp
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[options]
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.I device
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.SH DESCRIPTION
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\fBtunelp\fP sets several parameters for the /dev/lp\fI?\fP devices, for
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better performance (or for any performance at all, if your printer won't work
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without it...) Without parameters, it tells whether the device is using
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interrupts, and if so, which one. With parameters, it sets the device
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characteristics accordingly.
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.SH OPTIONS
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.TP
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\fB\-i\fR, \fB\-\-irq\fR \fIargument\fR
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specifies the IRQ to use for the parallel port in question. If this is set
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to something non-zero, \-t and \-c have no effect. If your port does not use
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interrupts, this option will make printing stop. The command
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.B tunelp -i 0
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restores non-interrupt driven (polling) action, and your printer should work
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again. If your parallel port does support interrupts, interrupt-driven
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printing should be somewhat faster and efficient, and will probably be
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desirable.
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.IP
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NOTE: This option will have no effect with kernel 2.1.131 or later since the
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irq is handled by the parport driver. You can change the parport irq for
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example via
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.IR /proc/parport/*/irq .
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Read
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.I /usr/src/linux/Documentation/parport.txt
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for more details on parport.
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.TP
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\fB\-t\fR, \fB\-\-time\fR \fImilliseconds\fR
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is the amount of time in jiffies that the driver waits if the printer doesn't
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take a character for the number of tries dictated by the \-c parameter. 10
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is the default value. If you want fastest possible printing, and don't care
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about system load, you may set this to 0. If you don't care how fast your
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printer goes, or are printing text on a slow printer with a buffer, then 500
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(5 seconds) should be fine, and will give you very low system load. This
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value generally should be lower for printing graphics than text, by a factor
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of approximately 10, for best performance.
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.TP
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\fB\-c\fR, \fB\-\-chars\fR \fIcharacters\fR
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is the number of times to try to output a character to the printer before
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sleeping for \-t \fITIME\fP. It is the number of times around a loop that
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tries to send a character to the printer. 120 appears to be a good value for
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most printers in polling mode. 1000 is the default, because there are some
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printers that become jerky otherwise, but you \fImust\fP set this to `1' to
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handle the maximal CPU efficiency if you are using interrupts. If you have a
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very fast printer, a value of 10 might make more sense even if in polling
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mode. If you have a \fIreally\fP old printer, you can increase this further.
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.IP
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Setting \-t \fITIME\fP to 0 is equivalent to setting \-c \fICHARS\fP to
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infinity.
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.TP
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\fB\-w\fR, \fB\-\-wait\fR \fImilliseconds\fR
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is the number of usec we wait while playing with the strobe signal. While
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most printers appear to be able to deal with an extremely short strobe, some
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printers demand a longer one. Increasing this from the default 1 may make it
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possible to print with those printers. This may also make it possible to use
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longer cables. It's also possible to decrease this value to 0 if your
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printer is fast enough or your machine is slow enough.
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.TP
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\fB\-a\fR, \fB\-\-abort\fR \fI<on|off>\fR
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This is whether to abort on printer error - the default is not to. If you
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are sitting at your computer, you probably want to be able to see an error
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and fix it, and have the printer go on printing. On the other hand, if you
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aren't, you might rather that your printer spooler find out that the printer
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isn't ready, quit trying, and send you mail about it. The choice is yours.
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.TP
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\fB\-o\fR, \fB\-\-check\-status\fR \fI<on|off>\fR
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This option is much like \-a. It makes any
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.BR open (2)
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of this device check to see that the device is on-line and not reporting any
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out of paper or other errors. This is the correct setting for most versions
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of lpd.
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.TP
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\fB\-C\fR, \fB\-\-careful\fR \fI<on|off>\fR
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This option adds extra ("careful") error checking. When this option is on,
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the printer driver will ensure that the printer is on-line and not reporting
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any out of paper or other errors before sending data. This is particularly
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useful for printers that normally appear to accept data when turned off.
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.IP
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NOTE: This option is obsolete because it's the default in 2.1.131 kernel or
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later.
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.TP
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\fB\-s\fR, \fB\-\-status\fR
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This option returns the current printer status, both as a decimal number from
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0..255, and as a list of active flags. When this option is specified, \-q
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off, turning off the display of the current IRQ, is implied.
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.TP
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\fB\-T\fR, \fB\-\-trust\-irq\fR \fI<on|off>\fR
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This option is obsolete. It was added in Linux 2.1.131, and removed again in
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Linux 2.3.10. The below is for these old kernels only.
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.IP
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This option tells the lp driver to trust or not the IRQ. This option makes
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sense only if you are using interrupts. If you tell the lp driver to trust
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the irq, then, when the lp driver will get an irq, it will send the next
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pending character to the printer unconditionally, even if the printer still
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claims to be BUSY. This is the only way to sleep on interrupt (and so the
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handle the irq printing efficiently) at least on Epson Stylus Color Printers.
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The lp driver automagically detects if you could get improved performance by
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setting this flag, and in such case it will warn you with a kernel message.
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.IP
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NOTE: Trusting the irq is reported to corrupt the printing on some hardware,
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you must try to know if your printer will work or not...
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.TP
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\fB\-r\fR, \fB\-\-reset\fR
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This option resets the port. It requires a Linux kernel version of 1.1.80 or
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later.
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.TP
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\fB\-q\fR, \fB\-\-print\-irq\fR \fI<on|off>\fR
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This option sets printing the display of the current IRQ setting.
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.SH NOTES
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.BR \-o ,
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.BR \-C ,
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and
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.B \-s
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all require a Linux kernel version of 1.1.76 or later.
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.PP
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.B \-C
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requires a Linux version prior to 2.1.131.
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.PP
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.B \-T
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requires a Linux version of 2.1.131 or later.
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.SH BUGS
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By some unfortunate coincidence the ioctl LPSTRICT of 2.0.36 has the same
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number as the ioctl LPTRUSTIRQ introduced in 2.1.131. So, use of the \-T
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option on a 2.0.36 kernel with an tunelp compiled under 2.1.131 or later may
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have unexpected effects.
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.SH FILES
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.I /dev/lp?
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.br
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.I /proc/parport/*/*
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.SH AVAILABILITY
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The tunelp command is part of the util-linux package and is available from
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.UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
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Linux Kernel Archive
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.UE .
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