NAME

     pnp — support for “Plug and Play” (PnP) ISA devices

DESCRIPTION

     The pnp driver enumerates ISA devices which support “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.

     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.

SEE ALSO

     pnpbios(4)

STANDARDS

     Intel and Microsoft, Plug and Play ISA Specification, Version 1.0a, May 5, 1994.

     Clarifications to the Plug and Play ISA Specification, Version 1.0a, December 10, 1994.

HISTORY

     The pnp driver first appeared in FreeBSD 2.2.5.  It has been substantially updated in
     subsequent versions.

AUTHORS

     PnP support was originally written for FreeBSD 2.2.5 by Luigi Rizzo, based on initial work
     done by Sujal Patel.

CAVEATS

     It is not possible to disable individual PnP ISA devices.  The pnp driver will find all
     devices conforming the PnP ISA specification and try to activate them all.

     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.