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Update the comments on values than can be returned by DEVICE_PROBE.

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DEVICE_PROBE can return priorities.

Reviewed by:	Doug Rabson <dfr@nlsystems.com>
This commit is contained in:
Nick Hibma 1999-06-17 19:22:12 +00:00
parent 1a95b917f0
commit 6979450036
2 changed files with 36 additions and 17 deletions
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36
share/man/man9/DEVICE_PROBE.9
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@ -26,7 +26,7 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $Id$
.\" $Id: DEVICE_PROBE.9,v 1.1 1998/09/03 21:52:04 dfr Exp $
.\"
.Dd June 16, 1998
.Os
@ -42,18 +42,36 @@
.Fn DEVICE_PROBE "device_t dev"
.Sh DESCRIPTION
.Pp
This device method should probe to see if the device is present. If
the device exists, the probe should return 0, otherwise ENXIO should
be returned. If some other error happens during the probe (such as a
memory allocation failure), an appropriate error code should be returned.
This device method should probe to see if the device is present.
It should return 0 if the device exists, ENXIO if it cannot be
found. If some other error happens during the probe (such as a memory
allocation failure), an appropriate error code should be returned. For
cases where more than one driver matches a device, a priority value can
be returned. In this case, success codes are values less than or equal
to zero with the highest value representing the best match. Failure
codes are represented by positive values and the regular unix error
codes should be used for the purpose.
.Pp
Devices which implement busses should use this method to probe for the
existence of devices attached to the bus and add them as children. If
this is combined with the use of
If a driver returns a success code which is less than zero, it must
not assume that it will be the same driver which is attached to the
device. In particular, it must not assume that any values stored in
the softc structure will be available for its attach method and any
resources allocated during probe must be released and re-allocated
if the attach method is called. If a success code of zero is
returned, the driver can assume that it will be the one attached.
.Pp
Devices which implement busses should use this method to probe for
the existence of devices attached to the bus and add them as
children. If this is combined with the use of
.Xr bus_generic_attach 9
the child devices will be automatically probed and attached.
.Sh RETURN VALUES
Zero is returned on success, otherwise an error is returned.
A value equal to or less than zero indicates success, greater than
zero indicates an error (errno). For values equal to or less than
zero: zero indicates highest priority, no further probing is done;
for a value less then zero, the lower the value the lower the
priority, e.g. -100 indicates a lower priority than -50.
.Sh SEE ALSO
.Xr device 9 ,
.Xr DEVICE_ATTACH 9

17
sys/kern/device_if.m
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@ -23,7 +23,7 @@
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $Id: device_if.m,v 1.4 1999/05/10 17:06:13 dfr Exp $
# $Id: device_if.m,v 1.5 1999/05/14 11:22:41 dfr Exp $
#
INTERFACE device;
@ -50,13 +50,14 @@ CODE {
#
# Probe to see if the device is present. Return 0 if the device exists,
# ENXIO if it cannot be found. For cases where more than one driver
# matches a device, a priority value can be returned. In this case,
# success codes are values less than or equal to zero with the highest
# value representing the best match. Failure codes are represented by
# positive values and the regular unix error codes should be used for
# the purpose.
#
# ENXIO if it cannot be found. If some other error happens during the
# probe (such as a memory allocation failure), an appropriate error code
# should be returned. For cases where more than one driver matches a
# device, a priority value can be returned. In this case, success codes
# are values less than or equal to zero with the highest value representing
# the best match. Failure codes are represented by positive values and
# the regular unix error codes should be used for the purpose.
# If a driver returns a success code which is less than zero, it must
# not assume that it will be the same driver which is attached to the
# device. In particular, it must not assume that any values stored in