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30 .Nd device control utility
82 utility adjusts the state of individual devices in the kernel's
83 internal device hierarchy.
86 consists of a single command followed by command-specific arguments.
87 Each command operates on a single device specified via the
92 may be specified either as the name of an existing device or as a
94 More details on supported address formats can be found in
97 The following commands are supported:
98 .Bl -tag -width indent
99 .It Cm attach Ar device
100 Force the kernel to re-probe the device.
101 If a suitable driver is found,
102 it is attached to the device.
107 Detach the device from its current device driver.
111 the device driver will be detached even if the device is busy.
117 If the device is currently attached to a device driver,
118 the device driver will be detached from the device,
119 but the device will retain its current name.
123 the device driver will be detached even if the device is busy.
124 .It Cm enable Ar device
126 The device will probe and attach if a suitable device driver is found.
127 Note that this can re-enable a device disabled at boot time via a
129 .It Cm suspend Ar device
131 This may include placing the device in a reduced power state.
132 .It Cm resume Ar device
133 Resume a suspended device to a fully working state.
138 Force the device to use a device driver named
140 If the device is already attached to a device driver and the
143 the device will be detached from its current device driver before it is
144 attached to the new device driver.
145 If the device is already attached to a device driver and the
147 flag is not specified,
148 the device will not be changed.
149 .It Xo Cm clear driver
153 Clear a previously-forced driver name so that the device is able to use any
155 After the previous name has been cleared,
156 the device is reprobed so that other device drivers may attach to it.
157 This can be used to undo an earlier
160 If the device is currently attached to a device driver and the
162 flag is not specified,
163 the device will not be changed.
164 .It Cm rescan Ar device
165 Rescan a bus device checking for devices that have been added or
171 Delete the device from the device tree.
175 the device will be deleted even if it is physically present.
176 This command should be used with care as a device that is deleted but present
177 can no longer be used unless the parent bus device rediscovers the device via
180 Freeze probe and attach processing initiated in response to drivers being
182 Drivers are placed on a
186 and processed when a later
192 Resume (thaw the freeze) probe and attach initiated in response to drivers
194 In addition to resuming, all pending actions that were frozen during the freeze
200 Reset the device, using bus-specific reset method.
201 Drivers for the devices being reset are suspended around the reset.
204 option is specified, drivers are detached instead.
206 Currently, resets are implemented for PCIe buses and PCI devices.
207 For PCIe bus, the link is disabled and then re-trained, causing all
208 children of the bus to reset.
213 tool to report parent bus for the device.
214 For PCI device, if Function-Level Reset is implemented by it, FLR is
215 tried first; if failed or not implemented, power reset is tried.
217 If you have detached or suspended a child device explicitly and then
218 do a reset, the child device will end up attached.
223 Prints the full path to the
227 method to get the path name.
232 locators are implemented.
233 The UEFI locator constructs a path to the device using the rules
234 outlines for DEVICE_PATH in the UEFI standard.
235 The FreeBSD locator constructs a path back to the root of the tree
236 with the nodes separated by slashes.
244 utility first appeared in
247 Currently there is no administrative flag to prevent re-attach or resume
248 of the manually detached or suspended devices after reset.
249 Similarly, there is no flag to prevent un-suspending of the manually
250 suspended devices after system resume.