DEVCTL(8)               FreeBSD System Manager's Manual              DEVCTL(8)

NAME
     devctl - device control utility

SYNOPSIS
     devctl attach device
     devctl clear driver [-f] device
     devctl detach [-f] device
     devctl disable [-f] device
     devctl enable device
     devctl suspend device
     devctl resume device
     devctl set driver [-f] device driver
     devctl rescan device
     devctl delete [-f] device
     devctl freeze
     devctl thaw
     devctl reset [-d] device

DESCRIPTION
     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.

     detach [-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.

     disable [-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.

     set driver [-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.

     clear driver [-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.

     delete [-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.

     reset [-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.

SEE ALSO
     devctl(3), devinfo(8)

HISTORY
     The devctl utility first appeared in FreeBSD 10.3.

BUGS
     Currently there is no administrative flag to prevent re-attach or resume
     of the manually detached or suspended devices after reset.  Similarly,
     there is no flag to prevent un-suspending of the the manually suspended
     devices after system resume.

FreeBSD 13.1-RELEASE-p6          June 1, 2021          FreeBSD 13.1-RELEASE-p6