This adds it to devctl, libdevctl, defines the two IOCTLs and implements the kernel bits. causes any new drivers that are added via kldload to be deferred until a 'thaw' comes in. These do not stack: it is an error to freeze while frozen, or thaw while thawed. Differential Revision: https://reviews.freebsd.org/D16735
395 lines
9.7 KiB
Groff
395 lines
9.7 KiB
Groff
.\"
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.\" Copyright (c) 2014 John Baldwin <jhb@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd August 29, 2016
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.Dt DEVCTL 3
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.Os
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.Sh NAME
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.Nm devctl ,
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.Nm devctl_attach ,
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.Nm devctl_clear_driver ,
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.Nm devctl_delete ,
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.Nm devctl_detach ,
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.Nm devctl_disable ,
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.Nm devctl_enable ,
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.Nm devctl_freeze ,
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.Nm devctl_rescan ,
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.Nm devctl_resume ,
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.Nm devctl_set_driver ,
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.Nm devctl_suspend ,
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.Nm devctl_thaw
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.Nd device control library
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.Sh LIBRARY
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.Lb libdevctl
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.Sh SYNOPSIS
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.In devctl.h
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.Ft int
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.Fn devctl_attach "const char *device"
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.Ft int
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.Fn devctl_clear_driver "const char *device" "bool force"
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.Ft int
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.Fn devctl_delete "const char *device" "bool force"
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.Ft int
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.Fn devctl_detach "const char *device" "bool force"
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.Ft int
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.Fn devctl_disable "const char *device" "bool force_detach"
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.Ft int
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.Fn devctl_enable "const char *device"
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.Ft int
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.Fn devctl_freeze "void"
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.Ft int
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.Fn devctl_rescan "const char *device"
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.Ft int
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.Fn devctl_resume "const char *device"
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.Ft int
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.Fn devctl_set_driver "const char *device" "const char *driver" "bool force"
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.Ft int
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.Fn devctl_suspend "const char *device"
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.Ft int
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.Fn devctl_thaw "void"
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.Sh DESCRIPTION
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The
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.Nm
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library adjusts the state of devices in the kernel's internal device
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hierarchy.
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Each control operation accepts a
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.Fa device
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argument that identifies the device to adjust.
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The
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.Fa device
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may be specified as either the name of an existing device or as a
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bus-specific address.
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The following bus-specific address formats are currently supported:
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.Bl -tag -offset indent
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.It Sy pci Ns Fa domain Ns : Ns Fa bus Ns : Ns Fa slot Ns : Ns Fa function
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A PCI device with the specified
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.Fa domain ,
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.Fa bus ,
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.Fa slot ,
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and
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.Fa function .
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.It Sy pci Ns Fa bus Ns : Ns Fa slot Ns : Ns Fa function
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A PCI device in domain zero with the specified
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.Fa bus ,
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.Fa slot ,
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and
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.Fa function .
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.It Fa handle
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A device with an ACPI handle of
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.Fa handle .
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The handle must be specified as an absolute path and must begin with a
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.Dq \e .
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.El
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.Pp
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The
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.Fn devctl_attach
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function probes a device and attaches a suitable device driver if one is
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found.
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.Pp
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The
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.Fn devctl_detach
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function detaches a device from its current device driver.
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The device is left detached until either a new driver for its parent
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bus is loaded or the device is explicitly probed via
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.Fn devctl_attach .
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If
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.Fa force
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is true,
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the current device driver will be detached even if the device is busy.
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.Pp
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The
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.Fn devctl_delete
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function deletes a device from the device tree.
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No
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If
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.Fa force
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is true,
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the device is deleted even if the device is physically present.
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.Pp
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The
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.Fn devctl_disable
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function disables a device.
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If the device is currently attached to a device driver,
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the device driver will be detached from the device,
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but the device will retain its current name.
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If
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.Fa force_detach
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is true,
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the current device driver will be detached even if the device is busy.
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The device will remain disabled and detached until it is explicitly enabled
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via
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.Fn devctl_enable .
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.Pp
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The
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.Fn devctl_enable
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function re-enables a disabled device.
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The device will probe and attach if a suitable device driver is found.
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.Pp
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The
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.Fn devctl_suspend
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function suspends a device.
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This may include placing the device in a reduced power state,
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but any device driver currently attached to the device will remain attached.
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.Pp
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The
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.Fn devctl_resume
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function resumes a suspended device to a fully working state.
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.Pp
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The
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.Fn devctl_set_driver
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function attaches a device driver named
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.Fa driver
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to a device.
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If the device is already attached and
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.Fa force
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is false,
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the request will fail.
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If the device is already attached and
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.Fa force
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is true,
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the device will be detached from its current device driver before it is
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attached to the new device driver.
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.Pp
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The
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.Fn devctl_clear_driver
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function resets a device so that it can be attached to any valid device
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driver rather than only drivers with a previously specified name.
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This function is used to undo a previous call to
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.Fn devctl_set_driver .
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If the device is already attached and
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.Fa force
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is false,
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the request will fail.
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If the device is already attached and
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.Fa force
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is true,
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the device will be detached from its current device driver.
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After the device's name is reset,
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it is reprobed and attached to a suitable device driver if one is found.
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.Pp
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The
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.Fn devctl_rescan
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function rescans a bus device checking for devices that have been added or
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removed.
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.Pp
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The
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.Fn devctl_freeze
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function freezes probe and attach processing initiated in response to
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drivers being loaded.
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.Pp
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The
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.Fn devctl_thaw
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function resumes (thaws the freeze) probe and attach processing
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initiated in response to drivers being loaded.
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.Sh RETURN VALUES
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.Rv -std devctl_attach devctl_clear_driver devctl_delete devctl_detach \
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devctl_disable devctl_enable devctl_suspend devctl_rescan devctl_resume \
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devctl_set_driver
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.Sh ERRORS
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In addition to specific errors noted below,
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all of the
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.Nm
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functions may fail for any of the errors described in
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.Xr open 2
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as well as:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The device name is too long.
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.It Bq Er ENOENT
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No existing device matches the specified name or location.
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.It Bq Er EPERM
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The current process is not permitted to adjust the state of
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.Fa device .
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.El
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.Pp
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The
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.Fn devctl_attach
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er EBUSY
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The device is already attached.
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.It Bq Er ENOMEM
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An internal memory allocation request failed.
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.It Bq Er ENXIO
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The device is disabled.
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.It Bq Er ENXIO
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No suitable driver for the device could be found,
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or the driver failed to attach.
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.El
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.Pp
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The
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.Fn devctl_detach
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er EBUSY
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The current device driver for
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.Fa device
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is busy and cannot detach at this time.
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Note that some drivers may return this even if
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.Fa force
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is true.
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.It Bq Er ENXIO
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The device is not attached to a driver.
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.It Bq Er ENXIO
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The current device driver for
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.Fa device
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does not support detaching.
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.El
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.Pp
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The
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.Fn devctl_enable
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er EBUSY
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The device is already enabled.
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.It Bq Er ENOMEM
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An internal memory allocation request failed.
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.It Bq Er ENXIO
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No suitable driver for the device could be found,
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or the driver failed to attach.
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.El
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.Pp
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The
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.Fn devctl_disable
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er EBUSY
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The current device driver for
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.Fa device
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is busy and cannot detach at this time.
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Note that some drivers may return this even if
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.Fa force_detach
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is true.
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.It Bq Er ENXIO
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The device is already disabled.
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.It Bq Er ENXIO
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The current device driver for
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.Fa device
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does not support detaching.
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.El
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.Pp
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The
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.Fn devctl_suspend
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er EBUSY
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The device is already suspended.
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.It Bq Er EINVAL
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The device to be suspended is the root bus device.
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.El
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.Pp
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The
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.Fn devctl_resume
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The device is not suspended.
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.It Bq Er EINVAL
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The device to be resumed is the root bus device.
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.El
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.Pp
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The
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.Fn devctl_set_driver
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er EBUSY
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The device is currently attached to a device driver and
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.Fa force
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is false.
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.It Bq Er EBUSY
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The current device driver for
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.Fa device
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is busy and cannot detach at this time.
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.It Bq Er EFAULT
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The
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.Fa driver
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argument points outside the process' allocated address space.
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.It Bq Er ENOENT
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No device driver with the requested name exists.
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.It Bq Er ENOMEM
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An internal memory allocation request failed.
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.It Bq Er ENXIO
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The device is disabled.
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.It Bq Er ENXIO
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The new device driver failed to attach.
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.El
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.Pp
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The
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.Fn devctl_clear_driver
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er EBUSY
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The device is currently attached to a device driver and
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.Fa force
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is false.
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.It Bq Er EBUSY
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The current device driver for
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.Fa device
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is busy and cannot detach at this time.
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.It Bq Er EINVAL
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The device is not configured for a specific device driver name.
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.It Bq Er ENXIO
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The device driver chosen after reprobing failed to attach.
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.El
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.Pp
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The
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.Fn devctl_rescan
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er ENXIO
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The device is not attached to a driver.
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.It Bq Er ENXIO
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The bus driver does not support rescanning.
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.El
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.Pp
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The
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.Fn devctl_delete
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er EBUSY
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The device is physically present and
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.Fa force
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is false.
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.It Bq Er EINVAL
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.Fa dev
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is the root device of the device tree.
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.El
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.Sh SEE ALSO
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.Xr devinfo 3 ,
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.Xr devstat 3 ,
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.Xr devctl 8
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.Sh HISTORY
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The
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.Nm
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library first appeared in
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.Fx 10.3 .
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.Sh BUGS
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If a device is suspended individually via
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.Fn devctl_suspend
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and the entire machine is subsequently suspended,
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the device will be resumed when the machine resumes.
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