wpa_supplicant signal levels

Jouni Malinen j
Sun Sep 5 09:10:36 PDT 2010

On Tue, Jul 06, 2010 at 11:29:47PM -0400, David A Benjamin wrote:

> Judging from output from other tools (iwlist) and the min_diff block
> at the end of wpa_supplicant_need_to_roam, it seems these values
> should actually be negative. Specifically, if one treats that number
> as a signed char instead of unsigned, everything matches up.

> I wrote a patch that attempts to replicate some of that logic,
> although it may be more complicated than is necessary; I think some
> of the complexity is for backwards-compatibility, which might not be
> necessary depending on wpa_supplicant's dependencies? In any case,
> it is attached. Again, I don't know how any of this works, so it's
> likely the patch is a bit off. But I think at least the logic to
> determine min_diff in wpa_supplicant_need_to_roam would be more
> accurate if level were determined correctly.

Thanks. As far as WEXT is concerned, I've pretty much given up on trying
to get signal levels reported correctly with all drivers taken into
account how differently these values are being used.. The exact
conversion did not really change much for wpa_supplicant in the past,
but the limitations on excessive roaming (relatively recent change) does
indeed now show some difference based on the absolute value. I don't
think this would work with all drivers, but I don't think the end result
is going to be worse either.

I had an earlier patch from Tim Chick is pending patch queue, too, but
it looks like it was doing more or less the same as your patch. Since
yours is against a newer wpa_supplicant tree version, I applied it now
to the development tree with a small change to fix build issue with

Jouni Malinen                                            PGP id EFC895FA

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