Philippe Gerum authored Aug 30, 2019 and Jan Kiszka committed Aug 30, 2019

Having the RTDM core return -EBADF to indicate that it does not manage
a file descriptor is a problem, as several drivers also raise this
error to notify userland about an aborted wait due to a connection
being dismantled (e.g. RTnet). In this case, libcobalt ends up
forwarding the aborted request to the glibc, which is wrong.

Switch from -EBADF to -EADV to notify userland that RTDM does not
manage a file descriptor, which cannot conflict with any sensible
error code the Cobalt core or any RTDM driver may return.

Signed-off-by: Philippe Gerum <rpm@xenomai.org>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>