From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wi0-f181.google.com ([209.85.212.181]:35813 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754046AbbCCJdw (ORCPT ); Tue, 3 Mar 2015 04:33:52 -0500 Received: by wivz2 with SMTP id z2so1793315wiv.0 for ; Tue, 03 Mar 2015 01:33:51 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1425374168.2450.17.camel@sipsolutions.net> References: <1423568924-11895-1-git-send-email-michal.kazior@tieto.com> <1425374168.2450.17.camel@sipsolutions.net> From: Krishna Chaitanya Date: Tue, 3 Mar 2015 15:03:31 +0530 Message-ID: (sfid-20150303_103356_579418_6B00FFD8) Subject: Re: [PATCH] mac80211: disable u-APSD queues by default To: Johannes Berg Cc: Michal Kazior , linux-wireless Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue, Mar 3, 2015 at 2:46 PM, Johannes Berg wrote: > On Tue, 2015-02-10 at 12:48 +0100, Michal Kazior wrote: >> Some APs experience problems when working with >> U-APSD. Decreasing the probability of that >> happening by using legacy mode for all ACs but VO >> isn't enough. >> >> Cisco 4410N originally forced us to enable VO by >> default only because it treated non-VO ACs as >> legacy. >> >> However some APs (notably Netgear R7000) silently >> reclassify packets to different ACs. Since u-APSD >> ACs require trigger frames for frame retrieval >> clients would never see some frames (e.g. ARP >> responses) or would fetch them accidentally after >> a long time. > > This makes me a little sad, but I've applied this and even added a Cc > stable tag due to the interoperability issues. > Mixed mode (uapsd + legacy) is not really the optimal configuration, where we expect STA to send trigger frames periodically to retrieve the DL packets (especially very first packet). But still if we want power save, i suggest going for All u-apsd (0xF), so that AP will inform us by setting the TIM bit and we can retrieve the first frame. (We have this patch internally and it works well).