*** This bug is a duplicate of bug 38278 *** I can confirm blacklisting the islsm driver works with the -20 kernel. I have done this by creating a file /etc/modprobe.d/prism54 with the following content: ---8<-------- blacklist islsm_pci blacklist islsm ---8<-------- jos -- prism54 no longer works https://launchpad.net/bugs/38238