I was trying to use an usb wireless adapter with ralink RT2870 chipset. Simply plugging it in didn't work, lsusb found this device but ip addr didn't show me the wlan0 interface.
I tried loading the driver module manually, but modprobe rt2800usb returned with error:
$this->bbcode_second_pass_code('', 'modprobe: ERROR: could not insert 'rt2800usb': Unknown symbol in module, or unknown parameter (see dmesg)')
and dmesg told me:
$this->bbcode_second_pass_code('', '[ 5068.293491] cfg80211: Unknown symbol prepare_to_wait (err 0)
[ 5068.293889] cfg80211: Unknown symbol preempt_schedule (err 0)')
Can somebody help me?