devctl(8) manual page

The devctl utility adjusts the state of individual devices in the kernel's internal device hierarchy. Each invocation of devctl consists of a single command followed by command-specific arguments. Each command operates on a single device specified via the device argument. The device may be specified either as the name of an existing device or as a bus-specific address. More details on supported address formats can be found in devctl(3).

The following commands are supported:

attach device

Force the kernel to re-probe the device. If a suitable driver is found, it is attached to the device.

[-f] device Detach the device from its current device driver. If the -f flag is specified, the device driver will be detached even if the device is busy.

[-f] device Disable a device. If the device is currently attached to a device driver, the device driver will be detached from the device, but the device will retain its current name. If the -f flag is specified, the device driver will be detached even if the device is busy.

enable device

Enable a device. The device will probe and attach if a suitable device driver is found. Note that this can re-enable a device disabled at boot time via a loader tunable.

suspend device

Suspend a device. This may include placing the device in a reduced power state.

resume device

Resume a suspended device to a fully working state.

[-f] device driver Force the device to use a device driver named driver. If the device is already attached to a device driver and the -f flag is specified, the device will be detached from its current device driver before it is attached to the new device driver. If the device is already attached to a device driver and the -f flag is not specified, the device will not be changed.

[-f] device Clear a previously-forced driver name so that the device is able to use any valid device driver. After the previous name has been cleared, the device is reprobed so that other device drivers may attach to it. This can be used to undo an earlier set driver command. If the device is currently attached to a device driver and the -f flag is not specified, the device will not be changed.

rescan device

Rescan a bus device checking for devices that have been added or removed.

[-f] device Delete the device from the device tree. If the -f flag is specified, the device will be deleted even if it is physically present. This command should be used with care as a device that is deleted but present can no longer be used unless the parent bus device rediscovers the device via a rescan request.

freeze

Freeze probe and attach processing initiated in response to drivers being loaded. Drivers are placed on a " frozen list " and processed when a later " thaw " occurs.

thaw Resume (thaw the freeze) probe and attach initiated in response to drivers being loaded. In addition to resuming, all pending actions that were frozen during the freeze are performed.

[-d] device Reset the device, using bus-specific reset method. Drivers for the devices being reset are suspended around the reset. If the -d option is specified, drivers are detached instead.
Currently, resets are implemented for PCIe buses and PCI devices. For PCIe bus, the link is disabled and then re-trained, causing all children of the bus to reset. Use -p option of devinfo(8) tool to report parent bus for the device. For PCI device, if Function-Level Reset is implemented by it, FLR is tried first; if failed or not implemented, power reset is tried.
If you have detached or suspended a child device explicitly and then do a reset, the child device will end up attached.

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Manual Pages — DEVCTL

NAME

CONTENTS

SYNOPSIS

DESCRIPTION

SEE ALSO

HISTORY

BUGS

attach device
	Force the kernel to re-probe the device. If a suitable driver is found, it is attached to the device.
[-f] device Detach the device from its current device driver. If the -f flag is specified, the device driver will be detached even if the device is busy.
[-f] device Disable a device. If the device is currently attached to a device driver, the device driver will be detached from the device, but the device will retain its current name. If the -f flag is specified, the device driver will be detached even if the device is busy.
enable device
	Enable a device. The device will probe and attach if a suitable device driver is found. Note that this can re-enable a device disabled at boot time via a loader tunable.
suspend device
	Suspend a device. This may include placing the device in a reduced power state.
resume device
	Resume a suspended device to a fully working state.
[-f] device driver Force the device to use a device driver named driver. If the device is already attached to a device driver and the -f flag is specified, the device will be detached from its current device driver before it is attached to the new device driver. If the device is already attached to a device driver and the -f flag is not specified, the device will not be changed.
[-f] device Clear a previously-forced driver name so that the device is able to use any valid device driver. After the previous name has been cleared, the device is reprobed so that other device drivers may attach to it. This can be used to undo an earlier set driver command. If the device is currently attached to a device driver and the -f flag is not specified, the device will not be changed.
rescan device
	Rescan a bus device checking for devices that have been added or removed.
[-f] device Delete the device from the device tree. If the -f flag is specified, the device will be deleted even if it is physically present. This command should be used with care as a device that is deleted but present can no longer be used unless the parent bus device rediscovers the device via a rescan request.
freeze
	Freeze probe and attach processing initiated in response to drivers being loaded. Drivers are placed on a " frozen list " and processed when a later " thaw " occurs.
thaw	Resume (thaw the freeze) probe and attach initiated in response to drivers being loaded. In addition to resuming, all pending actions that were frozen during the freeze are performed.
[-d] device Reset the device, using bus-specific reset method. Drivers for the devices being reset are suspended around the reset. If the -d option is specified, drivers are detached instead. Currently, resets are implemented for PCIe buses and PCI devices. For PCIe bus, the link is disabled and then re-trained, causing all children of the bus to reset. Use -p option of devinfo(8) tool to report parent bus for the device. For PCI device, if Function-Level Reset is implemented by it, FLR is tried first; if failed or not implemented, power reset is tried. If you have detached or suspended a child device explicitly and then do a reset, the child device will end up attached.