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devctl.h
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Editing: devctl.3
.\" .\" Copyright (c) 2014 John Baldwin <jhb@FreeBSD.org> .\" .\" 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 AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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 April 4, 2019 .Dt DEVCTL 3 .Os .Sh NAME .Nm devctl , .Nm devctl_attach , .Nm devctl_clear_driver , .Nm devctl_delete , .Nm devctl_detach , .Nm devctl_disable , .Nm devctl_enable , .Nm devctl_freeze , .Nm devctl_rescan , .Nm devctl_reset , .Nm devctl_resume , .Nm devctl_set_driver , .Nm devctl_suspend , .Nm devctl_thaw .Nd device control library .Sh LIBRARY .Lb libdevctl .Sh SYNOPSIS .In devctl.h .Ft int .Fn devctl_attach "const char *device" .Ft int .Fn devctl_clear_driver "const char *device" "bool force" .Ft int .Fn devctl_delete "const char *device" "bool force" .Ft int .Fn devctl_detach "const char *device" "bool force" .Ft int .Fn devctl_disable "const char *device" "bool force_detach" .Ft int .Fn devctl_enable "const char *device" .Ft int .Fn devctl_freeze "void" .Ft int .Fn devctl_rescan "const char *device" .Ft int .Fn devctl_reset "const char *device" "bool detach" .Ft int .Fn devctl_resume "const char *device" .Ft int .Fn devctl_set_driver "const char *device" "const char *driver" "bool force" .Ft int .Fn devctl_suspend "const char *device" .Ft int .Fn devctl_thaw "void" .Sh DESCRIPTION The .Nm library adjusts the state of devices in the kernel's internal device hierarchy. Each control operation accepts a .Fa device argument that identifies the device to adjust. The .Fa device may be specified as either the name of an existing device or as a bus-specific address. The following bus-specific address formats are currently supported: .Bl -tag -offset indent .It Sy pci Ns Fa domain Ns : Ns Fa bus Ns : Ns Fa slot Ns : Ns Fa function A PCI device with the specified .Fa domain , .Fa bus , .Fa slot , and .Fa function . .It Sy pci Ns Fa bus Ns : Ns Fa slot Ns : Ns Fa function A PCI device in domain zero with the specified .Fa bus , .Fa slot , and .Fa function . .It Fa handle A device with an ACPI handle of .Fa handle . The handle must be specified as an absolute path and must begin with a .Dq \e . .El .Pp The .Fn devctl_attach function probes a device and attaches a suitable device driver if one is found. .Pp The .Fn devctl_detach function detaches a device from its current device driver. The device is left detached until either a new driver for its parent bus is loaded or the device is explicitly probed via .Fn devctl_attach . If .Fa force is true, the current device driver will be detached even if the device is busy. .Pp The .Fn devctl_delete function deletes a device from the device tree. No If .Fa force is true, the device is deleted even if the device is physically present. .Pp The .Fn devctl_disable function disables a device. If the device is currently attached to a device driver, the device driver will be detached from the device, but the device will retain its current name. If .Fa force_detach is true, the current device driver will be detached even if the device is busy. The device will remain disabled and detached until it is explicitly enabled via .Fn devctl_enable . .Pp The .Fn devctl_enable function re-enables a disabled device. The device will probe and attach if a suitable device driver is found. .Pp The .Fn devctl_suspend function suspends a device. This may include placing the device in a reduced power state, but any device driver currently attached to the device will remain attached. .Pp The .Fn devctl_resume function resumes a suspended device to a fully working state. .Pp The .Fn devctl_set_driver function attaches a device driver named .Fa driver to a device. If the device is already attached and .Fa force is false, the request will fail. If the device is already attached and .Fa force is true, the device will be detached from its current device driver before it is attached to the new device driver. .Pp The .Fn devctl_clear_driver function resets a device so that it can be attached to any valid device driver rather than only drivers with a previously specified name. This function is used to undo a previous call to .Fn devctl_set_driver . If the device is already attached and .Fa force is false, the request will fail. If the device is already attached and .Fa force is true, the device will be detached from its current device driver. After the device's name is reset, it is reprobed and attached to a suitable device driver if one is found. .Pp The .Fn devctl_rescan function rescans a bus device checking for devices that have been added or removed. .Pp The .Fn devctl_freeze function freezes probe and attach processing initiated in response to drivers being loaded. .Pp The .Fn devctl_thaw function resumes (thaws the freeze) probe and attach processing initiated in response to drivers being loaded. .Pp The .Fn devctl_reset function resets the specified device using bus-specific reset method. The .Fa detach argument, if true, specifies that the device driver is detached before the reset, and re-attached afterwards. If false, the device is suspended before the reset, and resumed after. .Sh RETURN VALUES .Rv -std devctl_attach devctl_clear_driver devctl_delete devctl_detach \ devctl_disable devctl_enable devctl_suspend devctl_rescan devctl_resume \ devctl_set_driver .Sh ERRORS In addition to specific errors noted below, all of the .Nm functions may fail for any of the errors described in .Xr open 2 as well as: .Bl -tag -width Er .It Bq Er EINVAL The device name is too long. .It Bq Er ENOENT No existing device matches the specified name or location. .It Bq Er EPERM The current process is not permitted to adjust the state of .Fa device . .El .Pp The .Fn devctl_attach function may fail if: .Bl -tag -width Er .It Bq Er EBUSY The device is already attached. .It Bq Er ENOMEM An internal memory allocation request failed. .It Bq Er ENXIO The device is disabled. .It Bq Er ENXIO No suitable driver for the device could be found, or the driver failed to attach. .El .Pp The .Fn devctl_detach function may fail if: .Bl -tag -width Er .It Bq Er EBUSY The current device driver for .Fa device is busy and cannot detach at this time. Note that some drivers may return this even if .Fa force is true. .It Bq Er ENXIO The device is not attached to a driver. .It Bq Er ENXIO The current device driver for .Fa device does not support detaching. .El .Pp The .Fn devctl_enable function may fail if: .Bl -tag -width Er .It Bq Er EBUSY The device is already enabled. .It Bq Er ENOMEM An internal memory allocation request failed. .It Bq Er ENXIO No suitable driver for the device could be found, or the driver failed to attach. .El .Pp The .Fn devctl_disable function may fail if: .Bl -tag -width Er .It Bq Er EBUSY The current device driver for .Fa device is busy and cannot detach at this time. Note that some drivers may return this even if .Fa force_detach is true. .It Bq Er ENXIO The device is already disabled. .It Bq Er ENXIO The current device driver for .Fa device does not support detaching. .El .Pp The .Fn devctl_suspend function may fail if: .Bl -tag -width Er .It Bq Er EBUSY The device is already suspended. .It Bq Er EINVAL The device to be suspended is the root bus device. .El .Pp The .Fn devctl_resume function may fail if: .Bl -tag -width Er .It Bq Er EINVAL The device is not suspended. .It Bq Er EINVAL The device to be resumed is the root bus device. .El .Pp The .Fn devctl_set_driver function may fail if: .Bl -tag -width Er .It Bq Er EBUSY The device is currently attached to a device driver and .Fa force is false. .It Bq Er EBUSY The current device driver for .Fa device is busy and cannot detach at this time. .It Bq Er EFAULT The .Fa driver argument points outside the process' allocated address space. .It Bq Er ENOENT No device driver with the requested name exists. .It Bq Er ENOMEM An internal memory allocation request failed. .It Bq Er ENXIO The device is disabled. .It Bq Er ENXIO The new device driver failed to attach. .El .Pp The .Fn devctl_clear_driver function may fail if: .Bl -tag -width Er .It Bq Er EBUSY The device is currently attached to a device driver and .Fa force is false. .It Bq Er EBUSY The current device driver for .Fa device is busy and cannot detach at this time. .It Bq Er EINVAL The device is not configured for a specific device driver name. .It Bq Er ENXIO The device driver chosen after reprobing failed to attach. .El .Pp The .Fn devctl_rescan function may fail if: .Bl -tag -width Er .It Bq Er ENXIO The device is not attached to a driver. .It Bq Er ENXIO The bus driver does not support rescanning. .El .Pp The .Fn devctl_delete function may fail if: .Bl -tag -width Er .It Bq Er EBUSY The device is physically present and .Fa force is false. .It Bq Er EINVAL .Fa dev is the root device of the device tree. .El .Pp The .Fn devctl_reset function may fail if: .Bl -tag -width Er .It Bq Er ENXIO The bus does not implement the reset method. .It Bq Er ETIMEDOUT The device failed to respond after the reset in the time limits specific to the bus. .El The .Fn devctl_reset function may also return errors caused by the attach, detach, suspend, and resume methods of the device driver. .Sh SEE ALSO .Xr devinfo 3 , .Xr devstat 3 , .Xr devctl 8 .Sh HISTORY The .Nm library first appeared in .Fx 10.3 . .Sh BUGS If a device is suspended individually via .Fn devctl_suspend and the entire machine is subsequently suspended, the device will be resumed when the machine resumes. .Pp Similarly, if the device is suspended, and .Fn devctl_reset is called on the device with .Fa detach set to .Va false , the device is resumed by the .Fn devctl_reset call. Or, if the driver for the device is detached manually, and .Fn devctl_reset is called on the device with .Fa detach set to .Va true , device reset re-attaches the driver.
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