ask the bus driver to see if this device is still
() function requests
that the parent device driver of dev
see if the hardware represented by dev
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 system. 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);
This manual page was written by Warner Losh