.\" Copyright (c) 1997 Luigi Rizzo
.\"
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.\" $FreeBSD: head/share/man/man4/man4.i386/pnp.4 251298 2013-06-03 13:11:48Z emaste $
.\"
.Dd September 20, 2001
.Dt PNP 4 i386
.Os
.Sh NAME
.Nm pnp
.Nd support for
.Dq "Plug and Play"
(PnP) ISA devices
.Sh DESCRIPTION
The
.Nm
driver enumerates ISA devices which support
.Dq "Plug and Play ISA Specification"
in the system.
It assigns ISA bus resources (interrupt line, DMA channel, I/O ports,
and memory region) to each device and activates it.
.Pp
If it cannot assign necessary resources to a PnP ISA device without
causing conflict with other devices in the system,
the device will not be activated and will be unavailable
to programs.
.Sh SEE ALSO
.Xr pnpbios 4
.Sh STANDARDS
.Rs
.%A Intel
.%A Microsoft
.%T "Plug and Play ISA Specification, Version 1.0a"
.%D "May 5, 1994"
.Re
.Pp
.Rs
.%T "Clarifications to the Plug and Play ISA Specification, Version 1.0a"
.%D "December 10, 1994"
.Re
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 2.2.5 .
It has been substantially updated in subsequent versions.
.Sh AUTHORS
.An -nosplit
PnP support was originally written
for
.Fx 2.2.5
by
.An Luigi Rizzo ,
based on initial work done by
.An Sujal Patel .
.Sh CAVEATS
It is not possible to disable individual PnP ISA devices.
The
.Nm
driver will find all devices conforming the PnP ISA specification
and try to activate them all.
.Pp
There is no way to explicitly assign particular resource to
the PnP ISA device.
The resource assignment is fully automatic and there is
no provision for manual override.