NAME
device_get_state,
device_busy, device_unbusy,
device_is_alive —
manipulate device state
SYNOPSIS
#include
<sys/param.h>
#include <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);
DESCRIPTION
The current state of a device is accessed by callingdevice_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.
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
AUTHORS
This man page was written by Doug Rabson.