This bug affects at least Jaunty, Karmic and Lucid Lynx alpha 2 - I tested the behaviour on each with the latest kernels for the releases. I also tested its behaviour with EB4 that is based on Debian unstable, that kernel crashes as well. I suspect that Hardy is affected as well, because the owner of the laptop reported it hanging at times - Im supposing it happened after toggling the wlan off but am unable to confirm that.
Hardware affected is an Eee PC 701SD, with Realtek RTL8187SE chipset. The wlan itself works, and I am able to turn the card on using the Fn-F2 hotkeys, but when turning wlan off it causes a kernel panic and hard locks the machine necessitating poweroff via holding the power key for 5 seconds. This happens both when Im connected to a wireless network as well as when I am not, and it happens every time wlan is toggled off.
This machine is not my own and I need to send it back to the person I was upgrading it for, so I dont know how much additional information I can give later - I have the laptop for a couple more days tops. I think I will have to inform the owner about the problem and ask her not to use the wlan toggle key. My own Eee pcs, the regular 701 4GB model and 901 20GB model are not affected by this as they have a different wlan chipset, and after https://bugs.launchpad.net/ubuntu/+source/linux/+bug/404626 was fixed, they now work perfectly. From browsing forums I found out that other owners of this specific 701SD model also report that toggling wlan off causes a kernel crash every time, for example here: http://ubuntuforums.org/showthread.php?p=8819267#post8819267 others also tell of problems connecting to a WEP network - I have only used in WPA2 networks and there it worked, even though it sometimes drops the connection even when the laptop is right next to the router.
I installed kernel-crashdump and caused the panic, I will attach the Apport-generated crashdump. I tried to do that via Apports automatic bug reporting as well, but Apport itself reported an error connecting to the bug server and crashed when it had sent about 98% of the kernel crashdump, so Im not going to try that again as it took about an hour for the slow lappie to process that in any case.
The exact time of the crash was 21.00.54 on 14th of February. If you need additional information, please request it as soon as possible as I cannot keep the machine for much longer.
Bah, Launchpad had an error after my browser sent the 120 mb crash report and failed to upload it. I will see if I can upload it somewhere else and will post a link here ASAP.