FreeBSD manual

download PDF document: devctl.3.pdf

DEVCTL(3) FreeBSD Library Functions Manual DEVCTL(3) NAME devctl, devctl_attach, devctl_clear_driver, devctl_delete, devctl_detach, devctl_disable, devctl_enable, devctl_freeze, devctl_getpath, devctl_rescan, devctl_reset, devctl_resume, devctl_set_driver, devctl_suspend, devctl_thaw - device control library LIBRARY Device Control Library (libdevctl, -ldevctl) SYNOPSIS #include <devctl.h> int devctl_attach(const char *device); int devctl_clear_driver(const char *device, bool force); int devctl_delete(const char *device, bool force); int devctl_detach(const char *device, bool force); int devctl_disable(const char *device, bool force_detach); int devctl_enable(const char *device); int devctl_freeze(void); int devctl_getpath(const char *device, const char *locator, char **buffer); int devctl_rescan(const char *device); int devctl_reset(const char *device, bool detach); int devctl_resume(const char *device); int devctl_set_driver(const char *device, const char *driver, bool force); int devctl_suspend(const char *device); int devctl_thaw(void); DESCRIPTION The devctl library adjusts the state of devices in the kernel's internal device hierarchy. Each control operation accepts a device argument that pcibus:slot:function A PCI device in domain zero with the specified bus, slot, and function. handle A device with an ACPI handle of handle. The handle must be specified as an absolute path and must begin with a "\". The devctl_attach() function probes a device and attaches a suitable device driver if one is found. The devctl_detach() function detaches a device from its current device driver. The device is left detached until either a new driver for its parent bus is loaded or the device is explicitly probed via devctl_attach(). If force is true, the current device driver will be detached even if the device is busy. The devctl_delete() function deletes a device from the device tree. No If force is true, the device is deleted even if the device is physically present. The devctl_disable() function disables 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 force_detach is true, the current device driver will be detached even if the device is busy. The device will remain disabled and detached until it is explicitly enabled via devctl_enable(). The devctl_enable() function re-enables a disabled device. The device will probe and attach if a suitable device driver is found. The devctl_suspend() function suspends a device. This may include placing the device in a reduced power state, but any device driver currently attached to the device will remain attached. The devctl_resume() function resumes a suspended device to a fully working state. The devctl_set_driver() function attaches a device driver named driver to a device. If the device is already attached and force is false, the request will fail. If the device is already attached and force is true, the device will be detached from its current device driver before it is attached to the new device driver. The devctl_clear_driver() function resets a device so that it can be attached to any valid device driver rather than only drivers with a previously specified name. This function is used to undo a previous call to devctl_set_driver(). If the device is already attached and force is false, the request will fail. If the device is already attached and force is true, the device will be detached from its current device driver. After the device's name is reset, it is reprobed and attached to a suitable device driver if one is found. The devctl_rescan() function rescans a bus device checking for devices that have been added or removed. The devctl_getpath() retrieves the path to the device from the kernel using the locator method to construct the path. The buffer pointer is updated with an allocated buffer that must be freed with free. The devctl_reset() function resets the specified device using bus- specific reset method. The detach argument, if true, specifies that the device driver is detached before the reset, and re-attached afterwards. If false, the device is suspended before the reset, and resumed after. RETURN VALUES The devctl_attach(), devctl_clear_driver(), devctl_delete(), devctl_detach(), devctl_disable(), devctl_enable(), devctl_suspend(), devctl_rescan(), devctl_resume(), and devctl_set_driver() functions return the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS In addition to specific errors noted below, all of the devctl functions may fail for any of the errors described in open(2) as well as: [EINVAL] The device name is too long. [ENOENT] No existing device matches the specified name or location. [EPERM] The current process is not permitted to adjust the state of device. The devctl_attach() function may fail if: [EBUSY] The device is already attached. [ENOMEM] An internal memory allocation request failed. [ENXIO] The device is disabled. [ENXIO] No suitable driver for the device could be found, or the driver failed to attach. The devctl_detach() function may fail if: [EBUSY] The current device driver for device is busy and cannot detach at this time. Note that some drivers may return this even if force is true. [ENXIO] The device is not attached to a driver. [ENXIO] The current device driver for device does not support detaching. The devctl_enable() function may fail if: [EBUSY] The device is already enabled. [ENOMEM] An internal memory allocation request failed. [ENXIO] No suitable driver for the device could be found, or the driver failed to attach. The devctl_disable() function may fail if: [EBUSY] The current device driver for device is busy and cannot detach at this time. Note that some drivers The devctl_suspend() function may fail if: [EBUSY] The device is already suspended. [EINVAL] The device to be suspended is the root bus device. The devctl_resume() function may fail if: [EINVAL] The device is not suspended. [EINVAL] The device to be resumed is the root bus device. The devctl_set_driver() function may fail if: [EBUSY] The device is currently attached to a device driver and force is false. [EBUSY] The current device driver for device is busy and cannot detach at this time. [EFAULT] The driver argument points outside the process' allocated address space. [ENOENT] No device driver with the requested name exists. [ENOMEM] An internal memory allocation request failed. [ENXIO] The device is disabled. [ENXIO] The new device driver failed to attach. The devctl_clear_driver() function may fail if: [EBUSY] The device is currently attached to a device driver and force is false. [EBUSY] The current device driver for device is busy and cannot detach at this time. [EINVAL] The device is not configured for a specific device driver name. [ENXIO] The device driver chosen after reprobing failed to attach. The devctl_rescan() function may fail if: [ENXIO] The device is not attached to a driver. [ENXIO] The bus driver does not support rescanning. The devctl_delete() function may fail if: [EBUSY] The device is physically present and force is false. [EINVAL] dev is the root device of the device tree. The devctl_reset() function may fail if: SEE ALSO devinfo(3), devstat(3), devctl(8) HISTORY The devctl library first appeared in FreeBSD 10.3. BUGS If a device is suspended individually via devctl_suspend() and the entire machine is subsequently suspended, the device will be resumed when the machine resumes. Similarly, if the device is suspended, and devctl_reset() is called on the device with detach set to false, the device is resumed by the devctl_reset() call. Or, if the driver for the device is detached manually, and devctl_reset() is called on the device with detach set to true, device reset re-attaches the driver. FreeBSD 14.0-RELEASE-p11 April 4, 2019 FreeBSD 14.0-RELEASE-p11