mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-27 11:55:06 +00:00
88 lines
2.8 KiB
Groff
88 lines
2.8 KiB
Groff
.\" -*- nroff -*-
|
|
.\"
|
|
.\" Copyright (c) 2003 M. Warner Losh
|
|
.\"
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This program is free software.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
|
|
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd March 27, 2003
|
|
.Dt BUS_CHILD_PRESENT 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm bus_child_present
|
|
.Nd "ask the bus driver to see if this device is still really present"
|
|
.Sh SYNOPSIS
|
|
.In sys/param.h
|
|
.In sys/bus.h
|
|
.Pp
|
|
.In machine/bus.h
|
|
.In sys/rman.h
|
|
.In machine/resource.h
|
|
.Ft int
|
|
.Fn bus_child_present "device_t dev"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn bus_child_present
|
|
function requests that the parent device driver of
|
|
.Fa dev
|
|
check to see if the
|
|
hardware represented by
|
|
.Fa dev
|
|
is still physically accessible at this time.
|
|
While the notion of accessible varies from bus to bus, generally
|
|
hardware that is not accessible cannot be accessed via the
|
|
.Fn bus_space*
|
|
methods that would otherwise be used to access the device.
|
|
.Pp
|
|
This does not ask the question
|
|
.Dq does this device have children?
|
|
which can better be answered by
|
|
.Xr device_get_children 9 .
|
|
.Sh RETURN VALUES
|
|
A zero return value indicates that the device is not present in the
|
|
system.
|
|
A non-zero return value indicates that the device is present in the
|
|
system, or that the state of the device cannot be determined.
|
|
.Sh EXAMPLES
|
|
This is some example code.
|
|
It only calls stop when the
|
|
.Xr dc 4
|
|
device is actually present.
|
|
.Bd -literal -offset indent
|
|
device_t dev;
|
|
dc_softc *sc;
|
|
|
|
sc = device_get_softc(dev);
|
|
if (bus_child_present(dev))
|
|
dc_stop(sc);
|
|
.Ed
|
|
.Sh SEE ALSO
|
|
.Xr device 9 ,
|
|
.Xr driver 9
|
|
.Sh AUTHORS
|
|
This manual page was written by
|
|
.An Warner Losh Aq imp@FreeBSD.org .
|