Return-path: Received: from mail2.candelatech.com ([208.74.158.173]:53834 "EHLO mail2.candelatech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751327AbcISQTH (ORCPT ); Mon, 19 Sep 2016 12:19:07 -0400 Message-ID: <57E01026.9030604@candelatech.com> (sfid-20160919_181910_706641_36504C5E) Date: Mon, 19 Sep 2016 09:19:50 -0700 From: Ben Greear MIME-Version: 1.0 To: Johannes Berg , "Pedersen, Thomas" CC: linux-wireless Subject: Re: [PATCH] cfg80211: cap 20MHz VHT bitrate at MCS 8 References: <1473188417-13987-1-git-send-email-twp@qca.qualcomm.com> <2769a14e-964d-4ec2-9f04-ddd332434b78@candelatech.com> <38049c4f-da5b-a6ec-bcc4-c803197abcd7@qca.qualcomm.com> <1473662637.4201.2.camel@sipsolutions.net> <1473789454.27738.7.camel@qca.qualcomm.com> <1473789740.5622.3.camel@sipsolutions.net> <1474050629.31554.19.camel@qca.qualcomm.com> (sfid-20160916_203211_452910_08E25A89) <1474275637.4469.15.camel@sipsolutions.net> In-Reply-To: <1474275637.4469.15.camel@sipsolutions.net> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 09/19/2016 02:00 AM, Johannes Berg wrote: > >> Actually, can you apply the v2 (cfg80211: add bitrate for 20MHz MCS >> 9) of this? Systems guys confirmed they use MCS 9 @ 20MHz when LDPC >> is enabled. Also confirmed bitrate should be ok. > > I don't really understand that. How can the bitrate be "OK" when the > spec explicitly says it cannot be used? > > johannes > I think it is a moot point as far as this change goes: Regardless of whether the NIC should or not, it _does_. So, mis-reporting it up the stack only hides the issue and does not even give the user a clue that on-the-air encoding may be slightly off-spec. If the on-air encoding is an issue, then we need to hack the firmware to disable this 'feature', but that is a completely separate issue. Once this patch goes in, someone might consider properly reporting CCK rx rates for 5Ghz band too: ath10k can do this 'feature' as well, at least in some firmware. Probably can reproduce by sending off-channel mgt frames on 5Ghz when associated on 2.4, or something similar to this. I was using ath9k as sniffer when I found this long ago, so at least ath9k needs the change.... Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com