If you look in /var/log/syslog for cx88 entries you should see if the card's subsystem was recognised or it got detected as "generic/unknown". If its subsystem is set to 0000:0000 but the card is supported by the drivers, you'll need to force the card parameter.
But, if your card was detected and is supported (i.e. subsystem is not 0000:0000 and card is not generic/unknown) you'll need some firmware for it.
Let me know what your case is, maybe I can give you more info.