NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTES | BUGS | FILES | AVAILABILITY | COLOPHON

TUNELP(8)                   System Administration                  TUNELP(8)

NAME         top

       tunelp - set various parameters for the lp device

SYNOPSIS         top

       tunelp [options] device

DESCRIPTION         top

       tunelp sets several parameters for the /dev/lp? devices, for better
       performance (or for any performance at all, if your printer won't
       work 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.

OPTIONS         top

       -i, --irq argument
              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 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 desirable.

              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 /proc/parport/*/irq.
              Read /usr/src/linux/Documentation/parport.txt for more details
              on parport.

       -t, --time milliseconds
              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, --chars characters
              is the number of times to try to output a character to the
              printer before sleeping for -t TIME.  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 in
              polling mode.  1000 is the default, because there are some
              printers that become jerky otherwise, but you must 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
              really old printer, you can increase this further.

              Setting -t TIME to 0 is equivalent to setting -c CHARS to
              infinity.

       -w, --wait milliseconds
              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, --abort <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, --check-status <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, --careful <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.

              NOTE: This option is obsolete because it's the default in
              2.1.131 kernel or later.

       -s, --status
              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.

       -T, --trust-irq <on|off>
              This option is obsolete. It was added in Linux 2.1.131, and
              removed again in Linux 2.3.10.  The below is for these old
              kernels only.

              This option tells 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, --reset
              This option resets the port.  It requires a Linux kernel
              version of 1.1.80 or later.

       -q, --print-irq <on|off>
              This option sets printing the display of the current IRQ
              setting.

NOTES         top

       -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.

BUGS         top

       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.

FILES         top

       /dev/lp?
       /proc/parport/*/*

AVAILABILITY         top

       The tunelp  command is part of the util-linux package and is
       available from Linux Kernel Archive 
       ⟨ftp://ftp.kernel.org/pub/linux/utils/util-linux/⟩.

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.  If you have a
       bug report for this manual page, send it to
       util-linux@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository 
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2016-10-04.  If you discover any rendering problems in this HTML ver‐
       sion of the page, or you believe there is a better or more up-to-date
       source for the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original man‐
       ual page), send a mail to man-pages@man7.org

util-linux                      October 2011                       TUNELP(8)