Why does wireless need a wired connection to start it off?

I have got openSUSE 12.1 with KDE 4.7 (I think - the one that comes with 12.1 anyway) and have installed on my son’s laptop, having managed to get it working on my own (same make, very slightly different model).

Whenever I want to access the internet on my son’s PC, I need to plug an ethernet cable in and then watch as the wireless connection then starts to work. I can then unplug and, on first reboot, the wireless connection is there. After that, nothing. A scan does not even reveal the network, although the PC had no problem finding it when the ethernet cable was plugged in.

Has anyone any suggestions? What logs etc can I check for sources of the problem?

Assuming you are using plasmoid-networkmanagement,

to get a wireless connection both tick boxes need to be ticked,

  • Enable Networking
  • Enable Wireless

then under connections, you should only need to select the wireless connection,
if a connection has already been established via Manage Connections…