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33 .Nd device control utility
77 utility adjusts the state of individual devices in the kernel's
78 internal device hierarchy.
81 consists of a single command followed by command-specific arguments.
82 Each command operates on a single device specified via the
87 may be specified either as the name of an existing device or as a
89 More details on supported address formats can be found in
92 The following commands are supported:
93 .Bl -tag -width indent
94 .It Cm attach Ar device
95 Force the kernel to re-probe the device.
96 If a suitable driver is found,
97 it is attached to the device.
102 Detach the device from its current device driver.
106 the device driver will be detached even if the device is busy.
112 If the device is currently attached to a device driver,
113 the device driver will be detached from the device,
114 but the device will retain its current name.
118 the device driver will be detached even if the device is busy.
119 .It Cm enable Ar device
121 The device will probe and attach if a suitable device driver is found.
122 Note that this can re-enable a device disabled at boot time via a
124 .It Cm suspend Ar device
126 This may include placing the device in a reduced power state.
127 .It Cm resume Ar device
128 Resume a suspended device to a fully working state.
133 Force the device to use a device driver named
135 If the device is already attached to a device driver and the
138 the device will be detached from its current device driver before it is
139 attached to the new device driver.
140 If the device is already attached to a device driver and the
142 flag is not specified,
143 the device will not be changed.
144 .It Xo Cm clear driver
148 Clear a previously-forced driver name so that the device is able to use any
150 After the previous name has been cleared,
151 the device is reprobed so that other device drivers may attach to it.
152 This can be used to undo an earlier
155 If the device is currently attached to a device driver and the
157 flag is not specified,
158 the device will not be changed.
159 .It Cm rescan Ar device
160 Rescan a bus device checking for devices that have been added or
166 Delete the device from the device tree.
170 the device will be deleted even if it is physically present.
171 This command should be used with care as a device that is deleted but present
172 can no longer be used unless the parent bus device rediscovers the device via
178 Reset the device, using bus-specific reset method.
179 Drivers for the devices being reset are suspended around the reset.
182 option is specified, drivers are detached instead.
184 Currently, resets are implemented for PCIe buses and PCI devices.
185 For PCIe bus, the link is disabled and then re-trained, causing all
186 children of the bus to reset.
191 tool to report parent bus for the device.
192 For PCI device, if Function-Level Reset is implemented by it, FLR is
193 tried first; if failed or not implemented, power reset is tried.
195 If you have detached or suspended a child device explicitly and then
196 do a reset, the child device will end up attached.
199 Currently there is no administrative flag to prevent re-attach or resume
200 of the manually detached or suspended devices after reset.
201 Similarly, there is no flag to prevent un-suspending of the the manually
202 suspended devices after system resume.
209 utility first appeared in