On Tue, 2006-05-02 at 17:38 -0400, Dan Williams wrote: > On Sun, 2006-04-30 at 21:35 -0400, Darren Albers wrote: > > This was discussed in the past, the end result was that the Atheros > > card reports signal strength differently than other cards. I think > > Robert Love posted a patch for it but it was not implemented since the > > NM devs want to avoid making special case exceptions. > > > > Here are some links to previous discussions on the subject: > > http://mail.gnome.org/archives/networkmanager-list/2005-February/msg00063.html > > http://mail.gnome.org/archives/networkmanager-list/2006-January/msg00141.html > > > > Here is the madwifi teams take on the subject: > > http://madwifi.org/wiki/UserDocs/RSSI > > Current signal strength reporting for madwifi-ng is bogus and completely > broken WRT to the WE spec. > > max_qual is set to the theoretical max value of the variable (a u8 > type), and not the real-world max of the card. > > The 'qual' field of the WE quality is for link "quality", which is > subjective, while the "level" field is for the link's actual radio > levels. > > There are two options for the driver: > > 1) Actually use "quality": qual->qual must be bounded by 0 and > max_qual->qual, and must change in a linear fashion. It is defined as a > relative value, and therefore is a percentage. ipw2100 uses a signal > quality of 0 -> 100%, which is a combination of RSSI/dBm, packet loss, > link speed, missed beacons, etc. That is good. > > 2) Use the absolute or relative "levels" values: max_qual->level is 0 > and qual->level is a valid RSSI/dBm value, and qual->noise and/or > max_qual->noise is valid. OR: max_qual->level > 0, and qual->level is > valid. > > At least, that was the state when I last looked at the quality for > madwifi-ng, which was on Jan 26 2006, and also for r1475 from early > April. > > My comments in the NM strength calculation are: > > /* If the driver doesn't specify a complete and valid quality, we have > two options: > * > * 1) dBm: driver must specify max_qual->level = 0, and have valid > values for > * qual->level and (qual->noise OR max_qual->noise) > * 2) raw RSSI: driver must specify max_qual->level > 0, and have valid > values for > * qual->level and max_qual->level
Note that with WE-19 and later, a flag was added to specify that levels are explicitly in dBm, and therefore a max_qual->level of 0 is permitted provided that flag is present in the max_qual->updated and qual->updated fields. NM doesn't honor that particular flag yet, which is a valid bug against NM. But I don't think madwifi-ng does this at all, and therefore there's still a problem with madwifi. Dan > Just leaving it in RSSI without doing the proper encoding is a cop-out. > It's not up to userspace to figure out WTF the quality is, it's up to > the driver to present a sane view of it to the world, because only the > driver knows about the variations between chipsets and radios that each > card uses. Manufacturers have tables of how RSSI for their chipset and > radio map to dBm, and if the driver writers don't know that, then they > need to pick some empirical values and fake it. Stick your antenna > right next to an access point, and see what the highest RSSI is. Call > that 100%. Walk away until the signal drops. Call that 0%. If you're > in RSSI, you don't have to do anything else; that's your 0 -> 100% > range. If it's dBm, you have to code it from quadratic to linear. But > that's pretty simple. Madwifi kind of chickened out here. > > But the patch wouldn't be all that big. In reality, they've got bigger > problems, like not being upstream in the kernel and not using one of the > two softmac stacks that are now in the kernel (ipw+softmac and > devicescape). Madwifi is the black sheep and getting more so every > month... > > Dan > > > On 4/30/06, Pat Suwalski <[EMAIL PROTECTED]> wrote: > > > Hello, > > > > > > My ath_pci card is showing signal strength at about half of what it > > > should be. This is consistent with how iwlist shows it, but the GNOME > > > wireless applet has always shown it correctly. > > > > > > I don't know off-hand if it's always special cased, but it looks like it > > > might have to be. Maybe when they support the wireless extensions this > > > will be fixed. > > > > > > Any ideas? > > > > > > --Pat > > > _______________________________________________ > > > NetworkManager-list mailing list > > > [email protected] > > > http://mail.gnome.org/mailman/listinfo/networkmanager-list > > > > > _______________________________________________ > > NetworkManager-list mailing list > > [email protected] > > http://mail.gnome.org/mailman/listinfo/networkmanager-list > > _______________________________________________ > NetworkManager-list mailing list > [email protected] > http://mail.gnome.org/mailman/listinfo/networkmanager-list _______________________________________________ NetworkManager-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/networkmanager-list
