Manual Reference Pages - BUS_CHILD_PRESENT (9)
- ask the bus driver to see if this device is still really present
bus_child_present device_t dev
function requests that the parent device driver of
check to see if the
hardware represented by
is still physically accessible at this time.
While the notion of accessible varies from bus to bus, generally
hardware that is not accessible cannot be accessed via the
methods that would otherwise be used to access the device.
This does not ask the question
"does this device have children?"
which can better be answered by
A zero return value indicates that the device is not present in the
A non-zero return value indicates that the device is present in the
system, or that the state of the device cannot be determined.
This is some example code.
It only calls stop when the
device is actually present.
sc = device_get_softc(dev);
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.An Warner Losh Aq imp@FreeBSD.org .
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