xref: /freebsd/share/man/man4/lpt.4 (revision 953cd93fe64284ad8e2580f8acba0d45bbdba36b)

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.\" Copyright (c) 1994 Geoffrey M. Rehmet
.\" Copyright (c) 1998 Nicolas Souchu
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.Dd February 14, 1999
.Dt LPT 4
.Os FreeBSD
.Sh NAME
.Nm lpt
.Nd
Generic printer device driver
.Sh SYNOPSIS
.Cd "controller ppbus"
.Cd "device lpt at ppbus?"
.Pp
.Cd "controller	ppc0	at isa? port" \&"IO_LPT1\&" tty irq 7
.Cd "controller	ppc1	at isa? port" \&"IO_LPT2\&" tty irq 7
.Cd "controller	ppc2	at isa? port" \&"IO_LPT3\&" tty irq 7
.Pp
For BIOS-probed ports:
.Cd "controller ppc0 at isa? port? tty irq 7"
.Pp
For polled ports:
.Cd "controller ppc0 at isa? port? tty"
.Cd "controller ppc1 at isa? port" \&"IO_LPT2\&" tty
.Pp
For DMA capable parallel port:
.Cd "controller ppc0 at isa? port? tty irq 7 drq 1"
.Sh DESCRIPTION
The current
.Em lpt
driver is the port of the original lpt driver to the
.Xr ppbus 4
system.
.Pp
One purpose of this port was to allow parallel port sharing with other
parallel devices. Secondly, inb()/outb() calls have been replaced by ppbus
function calls. lpt is now arch-independent thanks to the ppbus interface. See
.Xr ppbus 4
for more info about the ppbus system.
.Pp
The parallel port bus is allocated by lpt when the printer device is opened
and released only when the transfer is completed: either when the device
is closed or when the entire buffer is sent in interrupt driven mode.
.Pp
The driver can be configured to be either interrupt-driven, or
to poll the printer.  Ports that are configured to be
interrupt-driven can be switched to polled mode by using the
.Xr lptcontrol 8
command.
.Pp
Depending on your hardware, extended capabilities may be configured with the
.Xr lptcontrol 8
command (use the -e option). With an ECP/ISA port, you can take advantage
of FIFO and DMA.
.Sh SEE ALSO
.Xr ppbus 4 ,
.Xr lptcontrol 8
.Sh HISTORY
This driver replaces the functionality of the lpa
driver, which is now defunct.
.Sh FILES
.Bl -tag -width Pa -compact
.It Pa /dev/lpt0
first parallel port driver
.El
.Sh BUGS
There are lots of them, especially in cheap parallel port implementations.
.Pp
It is only possible to open a lpt port when a printer is connected and
on-line, making it impossible to run
.Xr lptcontrol 8
when there is no printer connected.
.Pp
Please, ensure the
.Xr ppc 4
entry in you MACHINE file has the tty interrupt mask.
.Pp
This driver could still stand a rewrite.