Return-path: Received: from mail-wm0-f45.google.com ([74.125.82.45]:37829 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751472AbcAEKSU (ORCPT ); Tue, 5 Jan 2016 05:18:20 -0500 Received: by mail-wm0-f45.google.com with SMTP id f206so21565302wmf.0 for ; Tue, 05 Jan 2016 02:18:20 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <1451984419-5727-1-git-send-email-janusz.dziedzic@tieto.com> <20160105094504.GA3015@w1.fi> <20160105100659.GA3864@w1.fi> Date: Tue, 5 Jan 2016 11:18:19 +0100 Message-ID: (sfid-20160105_111824_600081_4B93BDEF) Subject: Re: [PATCH] mac80211: add use_minrate param to ieee80211_tx_prepare_skb() From: Janusz Dziedzic To: Jouni Malinen Cc: linux-wireless@vger.kernel.org, Johannes Berg Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 5 January 2016 at 11:16, Janusz Dziedzic wrote: > On 5 January 2016 at 11:06, Jouni Malinen wrote: >> On Tue, Jan 05, 2016 at 10:56:18AM +0100, Janusz Dziedzic wrote: >>> On 5 January 2016 at 10:45, Jouni Malinen wrote: >>> > On Tue, Jan 05, 2016 at 10:00:19AM +0100, Janusz Dziedzic wrote: >>> >> Add use_minrate param to ieee80211_tx_prepare_skb() function. >>> >> This is useful in case we would like to send frames >>> >> with lowest rates, eg. nullfunc, probe_resp. >>> > >>> > I could kind of understand this for short frames like Data nullfunc and >>> > PS-Poll, but why would we like to hard code Probe Response frames to be >>> > sent at the lowest rate? Shouldn't the frames be sent at a rate that is >>> > most likely to get them through and do so in a manner that does not use >>> > excessive amount of air time? >>> > >>> This is used to get/send probe_req() frame, next used by ath9k >>> "hw_scan" when chanctx used. >> >> Sure, but that's not what I'm asking. I'm asking why would we want to >> force Probe Response frames to use the lowest rate based on that commit >> message above. If that's a typo and should have been Probe Request >> frame, I'm going to ask the same question about Probe Request frames. >> Why would we like to force the lowest rate to be used for them? >> > I did it because most of devices I saw send probe_req using lowest rates? > Anyway I can skip this for probe_res() frames in next patch if this is > better idea. > BTW, should we export more params except minrate. I see also IEEE80211_TX_CTL_NO_CCK_RATE is used?? So, other implementation I see is to set info->flags |= IEEE80211_TX_CTL_NO_CCK_RATE | IEEE80211_TX_CTL_USE_MINRATE; In the driver and check this in ieee80211_tx_prepare_skb() before memset(0) in ieee80211_tx_prepare() I will send V2. BR Janusz