Comment 28 for bug 201202

Bob. Thanks for the patch. However, NetworkManager does not do the
roaming on its own; it is a wpasupplicant/driver decision to switch/disassoc
from the AP.

The output seen (and wrongly patched out by the patch) is NM reactively
updating its internal state _after_ wpasupplicant/driver did the roaming to (none).

The reason why we see this "roaming to (none)" symptom is that some
drivers (like atheros) are buggy when background scanning is
used. They often disassociate temporarily and that's when we see the
roaming to (none) in the log. We discussed this at UDS with
linville and friends and there is work on in progress to make drivers
behave better [1].

Also we thought and spec'ed to remove background scanning for karmic
[2], however with wifi consumers for geolocation (like in firefox),
its getting even more important that background scanning is done
regularly.

[1] - http://bugzilla.kernel.org/show_bug.cgi?id=12635#c7
[2] - https://wiki.ubuntu.com/DesktopTeam/Specs/Karmic/NetworkUI

Also see bug 291760 which is about background scanning issues.