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32 .Nd device control utility
84 utility adjusts the state of individual devices in the kernel's
85 internal device hierarchy.
88 consists of a single command followed by command-specific arguments.
89 Each command operates on a single device specified via the
94 may be specified either as the name of an existing device or as a
96 More details on supported address formats can be found in
99 The following commands are supported:
100 .Bl -tag -width indent
101 .It Cm attach Ar device
102 Force the kernel to re-probe the device.
103 If a suitable driver is found,
104 it is attached to the device.
109 Detach the device from its current device driver.
113 the device driver will be detached even if the device is busy.
119 If the device is currently attached to a device driver,
120 the device driver will be detached from the device,
121 but the device will retain its current name.
125 the device driver will be detached even if the device is busy.
126 .It Cm enable Ar device
128 The device will probe and attach if a suitable device driver is found.
129 Note that this can re-enable a device disabled at boot time via a
131 .It Cm suspend Ar device
133 This may include placing the device in a reduced power state.
134 .It Cm resume Ar device
135 Resume a suspended device to a fully working state.
140 Force the device to use a device driver named
142 If the device is already attached to a device driver and the
145 the device will be detached from its current device driver before it is
146 attached to the new device driver.
147 If the device is already attached to a device driver and the
149 flag is not specified,
150 the device will not be changed.
151 .It Xo Cm clear driver
155 Clear a previously-forced driver name so that the device is able to use any
157 After the previous name has been cleared,
158 the device is reprobed so that other device drivers may attach to it.
159 This can be used to undo an earlier
162 If the device is currently attached to a device driver and the
164 flag is not specified,
165 the device will not be changed.
166 .It Cm rescan Ar device
167 Rescan a bus device checking for devices that have been added or
173 Delete the device from the device tree.
177 the device will be deleted even if it is physically present.
178 This command should be used with care as a device that is deleted but present
179 can no longer be used unless the parent bus device rediscovers the device via
182 Freeze probe and attach processing initiated in response to drivers being
184 Drivers are placed on a
188 and processed when a later
194 Resume (thaw the freeze) probe and attach initiated in response to drivers
196 In addition to resuming, all pending actions that were frozen during the freeze
202 Reset the device, using bus-specific reset method.
203 Drivers for the devices being reset are suspended around the reset.
206 option is specified, drivers are detached instead.
208 Currently, resets are implemented for PCIe buses and PCI devices.
209 For PCIe bus, the link is disabled and then re-trained, causing all
210 children of the bus to reset.
215 tool to report parent bus for the device.
216 For PCI device, if Function-Level Reset is implemented by it, FLR is
217 tried first; if failed or not implemented, power reset is tried.
219 If you have detached or suspended a child device explicitly and then
220 do a reset, the child device will end up attached.
225 Prints the full path to the
229 method to get the path name.
234 locators are implemented.
235 The UEFI locator constructs a path to the device using the rules
236 outlines for DEVICE_PATH in the UEFI standard.
237 The FreeBSD locator constructs a path back to the root of the tree
238 with the nodes separated by slashes.
246 utility first appeared in
249 Currently there is no administrative flag to prevent re-attach or resume
250 of the manually detached or suspended devices after reset.
251 Similarly, there is no flag to prevent un-suspending of the manually
252 suspended devices after system resume.