It only takes 10 minutes to figure that this kind of cards are well supported in Linux.
- download the latest kernel (2.4.23 for the test)
- download the latest Prism54 patch
- Patch the kernel
- make dep; bzImage …
- download http://prism54.org/firmware/isl3890 in /usr/lib/hotplug/firmware/
- reboot and enjoy
You should get something like this:
Loaded prism54 driver, version 126.96.36.199 eth0: prism54_mib_init() eth0: islpci_open() eth0: resetting device... eth0: uploading firmware... eth0: firmware uploaded done, now triggering reset... eth0: prism54_mib_init() eth0: done with prism54_mib_init()! -- Client Managed mode
Latest point the README say that Ad-hoc mode for 2.4 kernel is a work in progress .. and it seems to work.