Up until kernel 2.6.22, the driver package released by the vendor AVM for their Fritz!WLAN USB stick worked pretty well for me. Unfortunately, after upgrading my system to a 2.6.23 kernel, I got reproducible segfaults whenever I tried to display any WLAN information, either through iwlist wlan0 scan or a plain iwconfig.
Naturally, this situation was annoying as hell, and I didn't intend to keep my system downgraded to a 2.6.22 kernel, so I tried searching for a solution. Most likely a lot like you at the moment. Unlike you, however, I didn't find a single site or forum or anything explaining and fixing the issue, so I contacted the vendor support asking for a patch I read of in some forums, but never actually saw.
To my surprise, I got a helpful and competent answer, along with the needed patch some other user created! Unfortunately I don't know who originally wrote the patch, but seeing it, it's a real non-issue. Who knows why AVM didn't already rereleased their driver with this patch incorporated. Anyway, I decided to give this patch a little more publicity, and here you go.
My 2.6.23 Arch Linux system is running just fine with the patched driver, after I disabled USB 2.0 support in my BIOS, which caused some random kernel crashes. That's most likely not a fault with the driver, though, as my board is rather old and always had flakey USB2.0 support. Some time ago I simply stopped caring.
Considering how simple the patch is, I see no issue in applying it concerning stability of the driver or kernel, at least not more than you'd risk by using the vanilla driver in the first place. However, use this patched driver at your own risk and discretion. Should the segfaults persist, double check that you correctly applied the patch and the kernel module has been correctly installed.
The first download, the tarball, is the original release of the vendor driver package for the AVM Fritz!WLAN USB stick, with the patch already applied to the sources. Just build it as you normally would, according to the enclosed readme file, and everything should be working fine, even on 2.6.23 kernels.
The second download is the patch only, in case you don't trust me and choose to apply it yourself to the vanilla driver package obtained from AVM after review.
Responsible for the contents of these pages (usually) is Dennis "Gyroplast" Herbrich, reachable by email at herbrich@veloxis.de.
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