wpa supplicant interface up delay

                         * Wait some time to allow driver to initialize before
                         * starting configuring the driver. This seems to be  
                         * needed at least some drivers that load firmware etc.
                         * when the interface is set up.

which drivers are those, and why can't we fix the drivers instead? This
seems like a bug in the drivers that they return from their open
callback prematurely.

johannes