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DEVICE_GET_STATE (9) | Kernel routines | Unix Manual Pages | :man

NAME

device_get_state, device_busy, device_unbusy, device_is_alive, device_is_attached - manipulate device state

CONTENTS

Synopsis
Description
See Also
Authors

SYNOPSIS


.In sys/param.h
.In sys/bus.h device_state_t device_get_state "device_t dev" void device_busy "device_t dev" void device_unbusy "device_t dev" int device_is_alive "device_t dev" int device_is_attached "device_t dev"

DESCRIPTION

The current state of a device is accessed by calling device_get_state which returns DS_NOTPRESENT, DS_ALIVE, DS_ATTACHED or DS_BUSY (described in device(9)). To test see if a device was successfully probed, call device_is_alive which simply returns if the state is greater or equal to DS_ALIVE. To test see if a device was successfully attached, call device_is_attached which simply returns if the state is greater or equal to DS_ATTACHED.

Each device has a busy count which is incremented when device_busy is called and decremented when device_unbusy is called. Both routines return an error if the device state is less than DS_ATTACHED.

When device_busy is called on a device in the DS_ATTACHED state, the device changes to the DS_BUSY state. When device_unbusy is called and after decrementing, the busy count for the device is zero, the device changes to the DS_ATTACHED state.

SEE ALSO

device(9)

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