The Prism54.org domain redirects here. The old website and drivers are archived at http://lekernel.net/prism54/.
p54 is a driver for Intersil's Prism54 chips series. It supports both older full-MAC devices (with new soft-MAC firmware) and newer soft-MAC devices. It is included in the Linux kernel.
Before you can use the hardware, you have to get the the right firmware.
- ISL3877, ISL3880, ISL3890 and ISL3886 (miniPCI)
ISL3886 + net2280 (USB, 1st generation with net2280 usb<->pci bridge)
- ISL3887 (USB, 2nd generation, native USB interface)
For a complete listing of supported products, see the device list.
There are several different firmwares for different hardware. so you have to pick the right one, download, rename to the listed name and put it into the right place... Normally this should be /lib/firmware. However some distributions put firmware in a different place.
Attention (USB 2nd generation users with < 2.6.28 kernels):
If you install the 2nd generation firmware and find that your USB device logs the message p54: LM87 firmware - not supported yet! then you need to download a buggy firmware right here and rename to isl3887usb_bare and put it into the right directory (as explained in the text above).
everyone else: please pick the right one for your device from this list
kernel >= 2.6.28
miniPCI / PCMCIA
USB 1st generation (ISL3886 + net2280)
USB 2nd generation (ISL3887)
Alternatively, firmware can be extracted from windows drivers with a tool called "fwextract3" available from http://lekernel.net/prism54/misc.html.
- Ad-Hoc, AP, Mesh, Monitor and Station Mode
- 802.11 a/b/g (on Duette, Frisbee, Crossbow RF frontend)
- WMM/WME/802.11e (QoS)
- TPC and ERP
- Cryptographic accelerator for WEP, TKIP and CCMP
- Packet Injection in Monitor Mode
not working yet
regulatory domain hints
Experimental patch: 
- LED class driver
- Firmware scanning
- DFS / Radar Detection
- NITRO (Burst, Compression, Aggregation)
- LowerMAC Terminal
powersave management in station mode
Experimental patch: 
Conexant's cx3110x / STMicroelectronics' / Nokia's stlc45xx (shmem/SPI-Interface) with a longbow frontend
To enable p54, you must first enable mac80211:
Networking ---> Wireless ---> <M> Improved wireless configuration API <M> Generic IEEE 802.11 Networking Stack (mac80211)
You can then enable p54 in the kernel configuration under
Device Drivers ---> [*] Network device support ---> Wireless LAN ---> [*] Wireless LAN (IEEE 802.11) <M> Softmac Prism54 support <M> Prism54 USB support <M> Prism54 PCI support