From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92C20C433DB for ; Fri, 5 Feb 2021 21:53:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 592AA64FB2 for ; Fri, 5 Feb 2021 21:53:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232892AbhBEVwz (ORCPT ); Fri, 5 Feb 2021 16:52:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230064AbhBEVwl (ORCPT ); Fri, 5 Feb 2021 16:52:41 -0500 Received: from mail-io1-xd33.google.com (mail-io1-xd33.google.com [IPv6:2607:f8b0:4864:20::d33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66520C06174A for ; Fri, 5 Feb 2021 13:52:01 -0800 (PST) Received: by mail-io1-xd33.google.com with SMTP id q7so8776293iob.0 for ; Fri, 05 Feb 2021 13:52:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=hbrb/uI0k3ZNQuj2wdQIApcZWfCHPVlwvdeH8dEraSY=; b=kwrr3ILLVbxuNn95GOVOzUFj/I8VbmFN7DHQIjWHdZ4hzEzqzgLDBrHY6JAB6GK4rj e9NBMfC+5XT+VMc3rHcgzSGPUBjZpe9BfKeQtVfxnQx7JCw3LkFBRSVq3WlAAEaSLcyd S/vGxA2CQGbb9/zj3fT0EvapZyFTHavASX7aM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=hbrb/uI0k3ZNQuj2wdQIApcZWfCHPVlwvdeH8dEraSY=; b=gKqXfSTVF/P3HsGip5SzakWa+uB7sPL9o7huQOcYXDDL4NLvKXU+jh68uhH+PJ9XOX Z7TGHlsqvAPYGJS7JtsAWch9ys2cbAXNcP9V0wvtR+3zn9yJqsJ0wtbsO4YsshuBd+5t O5oaZx5MUh8SY/YM6BtmDlSBuEVr1XBRB0v4R9UUUQIZee30ymgVHAMIJfcwkI1y1N1N iuUEk76J7kxRK19vmYgvYXfpO9gzm6UGcVyUxt1vPWX9lMTQHMuUExnuxyjVQ9tXXvlL 0LQfaFx8xFysKQOc9bTTd2dXAPaSauQG7ChUWU8EnLcVGKcb7/qro2pFfbMv17tjlfSw Vjfg== X-Gm-Message-State: AOAM533/1XeFmMKr8fTM+zCzhgJpL72gOUwCokqOZpqheKHwc5ky5w48 oWbPMyFzlV5lsKSqYwdBSvIeKWN+Rn98QPDElpDlgA== X-Google-Smtp-Source: ABdhPJzcxriljsqWdvwW4z6b5WmkyWMVNRVz8l3AqIltHdpJpTta6xksckQ68Rk6RRFHzAX843Ju+/a3m4NKaUf9cnc= X-Received: by 2002:a6b:7e41:: with SMTP id k1mr5944734ioq.81.1612561920905; Fri, 05 Feb 2021 13:52:00 -0800 (PST) MIME-Version: 1.0 References: <20201215172352.5311-1-youghand@codeaurora.org> In-Reply-To: From: Abhishek Kumar Date: Fri, 5 Feb 2021 13:51:49 -0800 Message-ID: Subject: Re: [PATCH 2/3] mac80211: Add support to trigger sta disconnect on hardware restart To: Youghandhar Chintala Cc: Felix Fietkau , Johannes Berg , "David S. Miller" , Jakub Kicinski , linux-wireless , netdev , LKML , Douglas Anderson , Brian Norris , Rakesh Pillai Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Since using DELBA frame to APs to re-establish BA session has a dependency on APs and also some APs may not honour the DELBA frame. I am fine with having the disconnect/reconnect solution. The change looks good to me. Reviewed-by: Abhishek Kumar Thanks Abhishek On Thu, Jan 28, 2021 at 12:08 AM wrote: > > On 2020-12-15 23:10, Felix Fietkau wrote: > > On 2020-12-15 18:23, Youghandhar Chintala wrote: > >> Currently in case of target hardware restart, we just reconfig and > >> re-enable the security keys and enable the network queues to start > >> data traffic back from where it was interrupted. > >> > >> Many ath10k wifi chipsets have sequence numbers for the data > >> packets assigned by firmware and the mac sequence number will > >> restart from zero after target hardware restart leading to mismatch > >> in the sequence number expected by the remote peer vs the sequence > >> number of the frame sent by the target firmware. > >> > >> This mismatch in sequence number will cause out-of-order packets > >> on the remote peer and all the frames sent by the device are dropped > >> until we reach the sequence number which was sent before we restarted > >> the target hardware > >> > >> In order to fix this, we trigger a sta disconnect, for the targets > >> which expose this corresponding wiphy flag, in case of target hw > >> restart. After this there will be a fresh connection and thereby > >> avoiding the dropping of frames by remote peer. > >> > >> The right fix would be to pull the entire data path into the host > >> which is not feasible or would need lots of complex changes and > >> will still be inefficient. > > How about simply tracking which tids have aggregation enabled and send > > DELBA frames for those after the restart? > > It would mean less disruption for affected stations and less ugly hacks > > in the stack for unreliable hardware. > > > > - Felix > > Hi Felix, > > We did try to send an ADDBA frame to the AP once the SSR happened. The > AP ack=E2=80=99ed the frame and the new BA session with renewed sequence = number > was established. But still, the AP did not respond to the ping requests > with the new sequence number. It did not respond until one of the two > happened. > 1. The sequence number was more than the sequence number that DUT ha= d > used before SSR happened > 2. DUT disconnected and then reconnected. > The other option is to send a DELBA frame to the AP and make the AP also > force to establish the BA session from its side. This we feel can have > some interoperability issues as some of the AP=E2=80=99s may not honour t= he > DELBA frame and will continue to use the earlier BA session that it had > established. Given that re-negotiating the BA session is prone to IOT > issues, we feel that it would be good to go with the > Disconnect/Reconnect solution which is foolproof and will work in all > scenarios. > > Regards, > Youghandhar