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32 .Nd device control utility
76 utility adjusts the state of individual devices in the kernel's
77 internal device hierarchy.
80 consists of a single command followed by command-specific arguments.
81 Each command operates on a single device specified via the
86 may be specified either as the name of an existing device or as a
88 More details on supported address formats can be found in
91 The following commands are supported:
92 .Bl -tag -width indent
93 .It Cm attach Ar device
94 Force the kernel to re-probe the device.
95 If a suitable driver is found,
96 it is attached to the device.
101 Detach the device from its current device driver.
105 the device driver will be detached even if the device is busy.
111 If the device is currently attached to a device driver,
112 the device driver will be detached from the device,
113 but the device will retain its current name.
117 the device driver will be detached even if the device is busy.
118 .It Cm enable Ar device
120 The device will probe and attach if a suitable device driver is found.
121 Note that this can re-enable a device disabled at boot time via a
123 .It Cm suspend Ar device
125 This may include placing the device in a reduced power state.
126 .It Cm resume Ar device
127 Resume a suspended device to a fully working state.
132 Force the device to use a device driver named
134 If the device is already attached to a device driver and the
137 the device will be detached from its current device driver before it is
138 attached to the new device driver.
139 If the device is already attached to a device driver and the
141 flag is not specified,
142 the device will not be changed.
143 .It Xo Cm clear driver
147 Clear a previously-forced driver name so that the device is able to use any
149 After the previous name has been cleared,
150 the device is reprobed so that other device drivers may attach to it.
151 This can be used to undo an earlier
154 If the device is currently attached to a device driver and the
156 flag is not specified,
157 the device will not be changed.
158 .It Cm rescan Ar device
159 Rescan a bus device checking for devices that have been added or
165 Delete the device from the device tree.
169 the device will be deleted even if it is physically present.
170 This command should be used with care as a device that is deleted but present
171 can no longer be used unless the parent bus device rediscovers the device via
177 Reset the device, using bus-specific reset method.
178 Drivers for the devices being reset are suspended around the reset.
181 option is specified, drivers are detached instead.
183 Currently, resets are implemented for PCIe buses and PCI devices.
184 For PCIe bus, the link is disabled and then re-trained, causing all
185 children of the bus to reset.
190 tool to report parent bus for the device.
191 For PCI device, if Function-Level Reset is implemented by it, FLR is
192 tried first; if failed or not implemented, power reset is tried.
194 If you have detached or suspended a child device explicitly and then
195 do a reset, the child device will end up attached.
198 Currently there is no administrative flag to prevent re-attach or resume
199 of the manually detached or suspended devices after reset.
200 Similarly, there is no flag to prevent un-suspending of the the manually
201 suspended devices after system resume.
208 utility first appeared in