Subject: Re: Missing link quality with wireless-testing
From: Johannes Berg <johannes@sipsolutions.net>
To: Dan Williams <dcbw@redhat.com>
Cc: Jouni Malinen <j@w1.fi>, Marcel Holtmann <marcel@holtmann.org>,
	linux-wireless@vger.kernel.org
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Date: Wed, 18 Feb 2009 15:25:44 +0100
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On Wed, 2009-02-18 at 07:48 -0500, Dan Williams wrote:

> > >   - max_qual.level =3D=3D 0 (ie, dBm values)
> >=20
> > That is an area where NM (=3D 0) and mac80211 (=3D -110) do not agree.
>=20
> Then mac80211 is not conforming to WEXT...  unless it's setting
> IW_QUAL_DBM in the updated field, which it probably is.

Yeah, it is.

> Before we added IW_QUAL_DBM, the switch between dBm and RSSI was
> max_qual.level; if it was 0, level was in dBm, because no cards in use
> in Linux at that time could support a signal of more 0 dBm.  Thus, if it
> was over 0, the value was in RSSI.
>=20
> Here's the relevant bit of wireless.h:
>=20
>         /* Quality range (link, level, noise)
>          * If the quality is absolute, it will be in the range [0 ; max_q=
ual],
>          * if the quality is dBm, it will be in the range [max_qual ; 0].
>=20
> That doc never got updated for IW_QUAL_DBM either.

Fun. But what did I expect. I withdraw my earlier patch then.

> NM doesn't really handle IW_QUAL_DBM (added in WE-19).  Mainly because
> stuff worked without it, and it wasn't implemented in drivers until
> quite recently.  NM should handle IW_QUAL_DBM.

Does all that mean that we cannot actually get this working right now
without adding back qual.qual? Or should we just remove IW_QUAL_DBM?

johannes

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