The recent release of ipw2100-0.52 contained a series of bugs which can lead to a kernel Oops when removing the module. Three patches were submitted to the pw2100-devel@lists.sourceforge.net mailing lists which fixes various issues with rmmod. Attached you will find these patches and an ipw2100-0.52-r1.ebuild which applies these.
Created attachment 37662 [details, diff] Patch for procfs entries
Created attachment 37663 [details, diff] Patch for rmmod issues with freeing IRQ
Created attachment 37664 [details, diff] Patch for rmmod issues with freeing IRQ
Created attachment 37665 [details, diff] Properly destroy the workqueue upon failed PCI probe
Created attachment 37666 [details] ipw2100-0.52-r1.ebuild which applies the above patches
Closing as WONTFIX since a new version (0.53) is out fixing those bugs. Please see bug #60791 for an ebuild for ipw2100-0.53.