linux-kernel - Re: 31-rc3-mmotm0716 - wonky wireless statistics..

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Date:	Mon, 03 Aug 2009 23:40:20 -0400
From:	Valdis.Kletnieks@...edu
To:	Johannes Berg <johannes@...solutions.net>
Cc:	Zhu Yi <yi.zhu@...el.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>
Subject: Re: 31-rc3-mmotm0716 - wonky wireless statistics..

On Wed, 29 Jul 2009 09:19:12 +0200, Johannes Berg said:

> > > # cat /proc/net/wireless
> > > Inter-| sta-|   Quality        |   Discarded packets               | Missed | WE
> > >  face | tus | link level noise |  nwid  crypt   frag  retry   misc | beacon | 22
> > >  wlan0: 0000   63.  -47.  -256        0      0      0      0      0
> > >  wlan1: 0000    0     0     0        0      0      0      0      0
> > >  wlan2: 0000    0     0     0        0      0      0      0      0

> and since we have dBm for the signal strength (and dBm is "all or
> nothing") you get -256 since we don't fill noise right now.
> 
> However, it goes on like this:
> 	stats->qual.updated & IW_QUAL_NOISE_UPDATED ? '.' : ' '
> 
> so you're right -- the tool shouldn't be using the value unless followed
> by a dot (".").

OK, went back and checked a -mmotm0702 kernel, and there I see:

 cat /proc/net/wireless
Inter-| sta-|   Quality        |   Discarded packets               | Missed | WE
 face | tus | link level noise |  nwid  crypt   frag  retry   misc | beacon | 22
 wlan0: 0000   64.  -46.  -127.       0      0      0      0      0        0
 wlan1: 0000    0     0     0        0      0      0      0      0        0
 wlan2: 0000    0     0     0        0      0      0      0      0        0

so yes, it appears that the userspace program (gkrellm-wifi) is failing to
notice the lack of a trailing '.'.  Looks like I need to write a patch and push
it upstream, make it do something sensible with the S/N ratio when N is
missing. Too bad probably no easy way to compute an estimate based on the level
and link-quality values....


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