ddi_get_devstate(9F) Kernel Functions for Drivers ddi_get_devstate(9F)NAMEddi_get_devstate - Check device state
SYNOPSIS
#include <sys/ddi.h>
#include <sys/sunddi.h>
ddi_devstate_t ddi_get_devstate(dev_info_t *dip);
INTERFACE LEVEL
Solaris DDI specific (Solaris DDI)
PARAMETERS
dip Pointer to the device's dev_info structure
DESCRIPTION
The ddi_get_devstate() function returns a value indicating the state of
the device specified by dip, as derived from the configuration opera‐
tions that have been performed on it (or on the bus on which it
resides) and any fault reports relating to it.
RETURN VALUES
DDI_DEVSTATE_OFFLINE
The device is offline. In this state, the device driver is not
attached, nor will it be attached automatically. The device cannot
be used until it is brought online.
DDI_DEVSTATE_DOWN
The device is online but unusable due to a fault.
DDI_DEVSTATE_QUIESCED
The bus on which the device resides has been quiesced. This is not
a fault, but no operations on the device should be performed while
the bus remains quiesced.
DDI_DEVSTATE_DEGRADED
The device is online but only able to provide a partial or
degraded service, due to a fault.
DDI_DEVSTATE_UP
The device is online and fully operational.
CONTEXT
The ddi_get_devstate() function may be called from user, kernel, or
interrupt context.
NOTES
A device driver should call this function to check its own state at
each major entry point, and before committing resources to a requested
operation. If a driver discovers that its device is already down, it
should perform required cleanup actions and return as soon as possible.
If appropriate, it should return an error to its caller, indicating
that the device has failed (for example, a driver's read(9E) routine
would return EIO).
Depending on the driver, some non-I/O operations (for example, calls to
the driver's ioctl(9E) routine) may still succeed; only functions which
would require fully accessible and operational hardware will necessar‐
ily fail. If the bus on which the device resides is quiesced, the
driver may return a value indicating the operation should be retried
later (for example, EAGAIN). Alternatively, for some classes of
device, it may be appropriate for the driver to enqueue the operation
and service it once the bus has been unquiesced. Note that not all
busses support the quiesce/unquiesce operations, so this value may
never be seen by some drivers.
SEE ALSOattach(9E), ioctl(9E), open(9E), read(9E), strategy(9E), write(9E),
ddi_dev_report_fault(9F)SunOS 5.10 13 August 1999 ddi_get_devstate(9F)
