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32 .Nd device control utility
80 utility adjusts the state of individual devices in the kernel's
81 internal device hierarchy.
84 consists of a single command followed by command-specific arguments.
85 Each command operates on a single device specified via the
90 may be specified either as the name of an existing device or as a
92 More details on supported address formats can be found in
95 The following commands are supported:
96 .Bl -tag -width indent
97 .It Cm attach Ar device
98 Force the kernel to re-probe the device.
99 If a suitable driver is found,
100 it is attached to the device.
105 Detach the device from its current device driver.
109 the device driver will be detached even if the device is busy.
115 If the device is currently attached to a device driver,
116 the device driver will be detached from the device,
117 but the device will retain its current name.
121 the device driver will be detached even if the device is busy.
122 .It Cm enable Ar device
124 The device will probe and attach if a suitable device driver is found.
125 Note that this can re-enable a device disabled at boot time via a
127 .It Cm suspend Ar device
129 This may include placing the device in a reduced power state.
130 .It Cm resume Ar device
131 Resume a suspended device to a fully working state.
136 Force the device to use a device driver named
138 If the device is already attached to a device driver and the
141 the device will be detached from its current device driver before it is
142 attached to the new device driver.
143 If the device is already attached to a device driver and the
145 flag is not specified,
146 the device will not be changed.
147 .It Xo Cm clear driver
151 Clear a previously-forced driver name so that the device is able to use any
153 After the previous name has been cleared,
154 the device is reprobed so that other device drivers may attach to it.
155 This can be used to undo an earlier
158 If the device is currently attached to a device driver and the
160 flag is not specified,
161 the device will not be changed.
162 .It Cm rescan Ar device
163 Rescan a bus device checking for devices that have been added or
169 Delete the device from the device tree.
173 the device will be deleted even if it is physically present.
174 This command should be used with care as a device that is deleted but present
175 can no longer be used unless the parent bus device rediscovers the device via
178 Freeze probe and attach processing initiated in response to drivers being
180 Drivers are placed on a
184 and processed when a later
190 Resume (thaw the freeze) probe and attach initiated in response to drivers
192 In addition to resuming, all pending actions that were frozen during the freeze
198 Reset the device, using bus-specific reset method.
199 Drivers for the devices being reset are suspended around the reset.
202 option is specified, drivers are detached instead.
204 Currently, resets are implemented for PCIe buses and PCI devices.
205 For PCIe bus, the link is disabled and then re-trained, causing all
206 children of the bus to reset.
211 tool to report parent bus for the device.
212 For PCI device, if Function-Level Reset is implemented by it, FLR is
213 tried first; if failed or not implemented, power reset is tried.
215 If you have detached or suspended a child device explicitly and then
216 do a reset, the child device will end up attached.
224 utility first appeared in
227 Currently there is no administrative flag to prevent re-attach or resume
228 of the manually detached or suspended devices after reset.
229 Similarly, there is no flag to prevent un-suspending of the the manually
230 suspended devices after system resume.