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

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

quoted

quoted

# 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....