Return-path: Received: from mail-bw0-f174.google.com ([209.85.218.174]:49789 "EHLO mail-bw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753063AbZEEQQh (ORCPT ); Tue, 5 May 2009 12:16:37 -0400 Received: by bwz22 with SMTP id 22so1404092bwz.37 for ; Tue, 05 May 2009 09:16:36 -0700 (PDT) Subject: RE: [ipw3945-devel] IWL3945 always reports noise levels of -127 From: Maxim Levitsky To: "Cahill, Ben M" Cc: iwlwifi maling list , linux-wireless In-Reply-To: <1241535034.4816.20.camel@maxim-laptop> References: <1241213459.7082.54.camel@maxim-laptop> <02B3067C068D0549A8CCFCB17D4D318B3569A43A@orsmsx502.amr.corp.intel.com> <1241463816.4816.1.camel@maxim-laptop> <02B3067C068D0549A8CCFCB17D4D318B3569A442@orsmsx502.amr.corp.intel.com> <1241535034.4816.20.camel@maxim-laptop> Content-Type: text/plain Date: Tue, 05 May 2009 19:16:30 +0300 Message-Id: <1241540190.4816.25.camel@maxim-laptop> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue, 2009-05-05 at 17:50 +0300, Maxim Levitsky wrote: > On Mon, 2009-05-04 at 12:27 -0700, Cahill, Ben M wrote: > > > > >-----Original Message----- > > >From: Maxim Levitsky [mailto:maximlevitsky@gmail.com] > > >Sent: Monday, May 04, 2009 3:04 PM > > >To: Cahill, Ben M > > >Cc: iwlwifi maling list; linux-wireless > > >Subject: RE: [ipw3945-devel] IWL3945 always reports noise > > >levels of -127 > > > > > >On Mon, 2009-05-04 at 11:53 -0700, Cahill, Ben M wrote: > > >> When one of our devices cannot figure out what the actual > > >noise level is, it reports -127. > > >> > > >> Newer devices are better at old devices at figuring noise > > >level. IIRC, 3945 cannot figure noise for CCK signals, and > > >may not be possible with OFDM as well. > > > > > >Why then it did work on older kernel ? > > >(and noise levels seemed to be correct) > > > > Hmmm, good point, and I don't know the answer! :-( > > > > And I do know it now (this is what I suspected...) > This is firmware issue. > > I forced the driver to use older firmware iwlwifi-3945-1.ucode, > and noise levels are back. Indeed old microcode reports values like that: rssi:017 agc:000 sig_avg:5437 noise_diff:580 New microcode reports this instead: rssi:018 agc:000 sig_avg:140 noise_diff:000 noise_diff is always zero now, and range for sig_avg changed. I also noticed that with older firmware I couldn't set the tx speed Thus what recently fixed it was a firmware update! (But in both cases OFDM rated were used) Thats all nothing to debug any more here. Best regards, Maxim Levitsky