Return-path: Received: from smtp.codeaurora.org ([198.145.29.96]:35693 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755696AbbLAJsj (ORCPT ); Tue, 1 Dec 2015 04:48:39 -0500 From: Kalle Valo To: Arend van Spriel Cc: linux-wireless , Hante Meuleman Subject: Re: [PATCH 08/11] brcmfmac: Make 5G join preference configurable. References: <1448447567-12189-1-git-send-email-arend@broadcom.com> <1448447567-12189-9-git-send-email-arend@broadcom.com> <87si3nkb2l.fsf@kamboji.qca.qualcomm.com> <565D5B77.7050501@broadcom.com> Date: Tue, 01 Dec 2015 11:48:32 +0200 In-Reply-To: <565D5B77.7050501@broadcom.com> (Arend van Spriel's message of "Tue, 1 Dec 2015 09:33:59 +0100") Message-ID: <87d1uqijnz.fsf@kamboji.qca.qualcomm.com> (sfid-20151201_104851_777160_94A1EA9B) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-wireless-owner@vger.kernel.org List-ID: Arend van Spriel writes: > On 11/30/2015 11:58 AM, Kalle Valo wrote: >> Arend van Spriel writes: >> >>> From: Hante Meuleman >>> >>> By default the 5G band has an advantage of 8 dBm on the RSSI when >>> it comes to selection during join and roam. This patch adds a >>> module param to make this value configurable. Using the value 99 >>> results in configuration that 5G has always preference over 2.4G. >>> >>> Reviewed-by: Arend Van Spriel >>> Reviewed-by: Franky (Zhenhui) Lin >>> Reviewed-by: Pieter-Paul Giesberts >>> Signed-off-by: Hante Meuleman >>> Signed-off-by: Arend van Spriel >> >> [...] >> >>> +/* Module param joinboost_5g used for preferred join selection. >>> + * Use value 99 to configure preferred join to choose 5G always over 2.4G, any >>> + * other value configures the advantage of 5G signal strength over 2.4G signal >>> + * strength. >>> + */ >>> +static int brcmf_joinboost_5g_rssi = BRCMF_JOIN_PREF_RSSI_BOOST; >>> +module_param_named(joinboost_5g, brcmf_joinboost_5g_rssi, int, 0); >>> +MODULE_PARM_DESC(joinboost_5g, "Join preference 5G RSSI boost"); >> >> I'm not sure here, is a module parameter really the right way to >> configure something like this? > > Define "right way". Something which can be generic for all drivers/hw with similar design. It's not good if a user is forced to configure this differently for each driver. I have understood that this is a common problem anyway. > It solves a problem for us, but admittedly it is not something that is > very usable by user-space apps. So I guess what you are suggesting > here is to come up with a nl80211 api for this. On the mailing list > (or hostap list) the topic pops up from time to time so there are > people who would like to have such a knob to play with. Still would > like to keep the module parameter although its use may change when > nl80211 api is added. I don't know what is the best approach, that's why I would like to hear opinions from others. Personally I don't like the idea of adding 802.11 level configuration options to module parameters, but on the other hand I don't have any strong opinions about this. I guess we have two different designs, one where the roaming logic is in firmware and other where wpasupplicant is responsible for this. (And I assume that brcfmac belongs to the former group.) Ideally it would be nice that we would have a same configuration knob for both but I don't know if that's really feasible. -- Kalle Valo