How to cleanly unload libertas module

[Holger Schurig]

> When I do an ifdown to unregister the wlan interface, and I
> try to unload the libertas_cs and libertas modules, it does't
> work because rmmod says me that the module is busy.

Works for me (with compact flash):

ifdown eth1
pccardctl eject
rmmod libertas_cs
rmmod libertas

Note that, because the CF driver registered itself with the 
PCMCIA subsystem, just doing "ifdown eth1" doesn't set the usage 
count to 0. After all, you can still access the card when the 
interface is down. Maybe the same is true for SDIO. You must do 
your SDIO-equivalent of "pccardctl eject", so that the driver 
get's de-registered. In the SDIO case, you must trigger that the 
SDIO subsystem calls your if_sdio_remove() function.