Return-path: Received: from mail.neratec.com ([46.140.151.2]:34356 "EHLO mail.neratec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752129AbaAPLsZ (ORCPT ); Thu, 16 Jan 2014 06:48:25 -0500 Message-ID: <52D7C62F.2030307@neratec.com> (sfid-20140116_124828_468633_360F2E6C) Date: Thu, 16 Jan 2014 12:44:47 +0100 From: Wojciech Dubowik MIME-Version: 1.0 To: Sujith Manoharan CC: ath9k-devel@lists.ath9k.org, linux-wireless@vger.kernel.org Subject: Re: [PATCH 5/5] ath9k: Fix TX IQ calibration for SoC chips References: <1384665016-12022-1-git-send-email-sujith@msujith.org> <1384665016-12022-5-git-send-email-sujith@msujith.org> <52CE934D.1020400@neratec.com> <21198.40916.260973.48444@gargle.gargle.HOWL> <52CEA5A3.2040308@neratec.com> <21198.43395.235654.597422@gargle.gargle.HOWL> <52CEAB24.5090700@neratec.com> <52D3F962.1010302@neratec.com> <21204.319.492595.58625@gargle.gargle.HOWL> <52D402C3.3070606@neratec.com> <21204.1991.201080.986559@gargle.gargle.HOWL> <21204.2384.710460.402183@gargle.gargle.HOWL> <21204.3832.404821.109119@gargle.gargle.HOWL> <52D63EBB.7020607@neratec.com> <21206.17284.157496.206327@gargle.gargle.HOWL> <52D6472B.2060207@neratec.com> <21207.48441.292580.481850@gargle.gargle.HOWL> <21207.49245.151249.759167@gargle.gargle.HOWL> In-Reply-To: <21207.49245.151249.759167@gargle.gargle.HOWL> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 01/16/2014 12:19 PM, Sujith Manoharan wrote: > Sujith Manoharan wrote: >> We could fix this by checking if we are initializing the history for the operating >> channel and waiting for NF-cal completion, but I am not sure if this needs >> to be done. The window is really small and subsequent NF calibrations using >> the ANI routine work properly. > Also, this is a bad idea in general since NF calibration has to > wait for the medium to become idle - problematic when there is heavy > interference or general WLAN usage. > > Sujith I guess I won't be able to reproduce bad scan results with wireless testing since I have changed scan reporting to pure rssi in my openwrt compat. In normal case you get a sum of rssi and noise floor and it will be correct i.e. when NF is shifted by 14db so will be rssi. So it's just my use case. Anyway I have just solved the issue by applying calibrated noise floor values from eeprom instead of nominal in nf_get functions and nf histogram. Now the rssi seems stable in my test environment. I have just started testing but it looks promising. I don't know whether it's worth changing it upstream since most of available ar9003 cards I have seen are not noise floor calibrated. A bit bad becasue it could be used for spectral scan as well to improve accuracy. Wojtek