OSN devices currently spend an awful long time in qeth_l2_set_online() until various unsupported HW cmds time out. This has been broken for over two years, ever since commit d22ffb5a712f ("s390/qeth: fix IPA command submission race") triggered a FW bug in cmd processing. Prior to commit 782e4a792147 ("s390/qeth: don't poll for cmd IO completion"), this wait for timeout would have even been spent busy-polling. The offending patch was picked up by stable and all relevant distros, and yet noone noticed. OSN setups only ever worked in combination with an out-of-tree blob, and the last machine that even offered HW with OSN support was released back in 2015. Rather than attempting to work-around this FW issue for no actual gain, add a deprecation warning so anyone who still wants to maintain this part of the code can speak up. Else rip it all out in 2021. Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>