Return-path: Received: from nbd.name ([46.4.11.11]:33937 "EHLO nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752366Ab2DOKbr (ORCPT ); Sun, 15 Apr 2012 06:31:47 -0400 Message-ID: <4F8AA38E.1040702@openwrt.org> (sfid-20120415_123150_561635_4ACC050D) Date: Sun, 15 Apr 2012 12:31:42 +0200 From: Felix Fietkau MIME-Version: 1.0 To: Gabor Juhos CC: "John W. Linville" , linux-wireless@vger.kernel.org, "ath9k-devel@lists.ath9k.org" Subject: Re: [PATCH 1/3] ath9k: use consistent value for REDUCE_SCALED_POWER_BY_THREE_CHAIN References: <1334433719-1144-1-git-send-email-juhosg@openwrt.org> In-Reply-To: <1334433719-1144-1-git-send-email-juhosg@openwrt.org> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 2012-04-14 10:01 PM, Gabor Juhos wrote: > The REDUCE_SCALED_POWER_BY_THREE_CHAIN symbol is > defined in different eeprom files, and the value > varies between the different files. > > In eeprom_def.c and in ar9003_eeprom.c the value > of the symbol is 9, however the comments in these > files indicates the value should be 10*log10(3)*2 > which is 9.54242509439325. Replace the the value > to 10 in these files. > > Also add comments to eeprom_9287.c. > > Signed-off-by: Gabor Juhos I think we should keep the value 9. If I understand the logic behind the power increase through chain combining properly, this value only describes the worst-case (wrt. regulatory compliance) upper limit of tx power, whereas in practice the measured combined power output will be much lower than that due to signal/phase differences. Regulatory compliance is already properly tested on all devices with the truncated value 9, so I don't think that we need to be even more conservative and round up here. - Felix