From patchwork Wed Mar 4 02:12:10 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergey Ryazanov X-Patchwork-Id: 5927881 X-Patchwork-Delegate: kvalo@adurom.com Return-Path: X-Original-To: patchwork-linux-wireless@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 115DEBF440 for ; Wed, 4 Mar 2015 02:12:25 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id F1C092044B for ; Wed, 4 Mar 2015 02:12:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD5C62043C for ; Wed, 4 Mar 2015 02:12:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755108AbbCDCMU (ORCPT ); Tue, 3 Mar 2015 21:12:20 -0500 Received: from mail-lb0-f174.google.com ([209.85.217.174]:45987 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752805AbbCDCMT (ORCPT ); Tue, 3 Mar 2015 21:12:19 -0500 Received: by lbiz12 with SMTP id z12so13346005lbi.12 for ; Tue, 03 Mar 2015 18:12:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=utBS0bVjcjImZto0CuA8D+O6Gzo8bsDf+Lk8SGMXYoY=; b=EknsR1evlQ3dAmDUGwdRX3iETgeM2n26Df0TcRiZ39535tdX1CwWYP1k0QJf0aJ1Dq LmoqSUBPovlwQhkX+TJX7j4SmQ8n6VFxm55dbSXSC7S9PQ3zL4d77mjIu0z4YTK5WVNv VjkfVbvfvSofYQWVuUa+Q/rcEtqf7d2DzcU7TxM0rF1Tvgr9OLdJGWLcy2Rv9DZ+2qDv AKOAFd/hsJcFZRlqisoiNripkoNwDfocrD6IybhalKuCzf4JC0Hih6HQuvjPX0REiyoM /SO5teNqe4EsCr/KJBRv7uD93qV7Ky9VaZXtGesfa6QtxZwzhfEaSSJ1HfZYpoANe5TY nvzw== X-Received: by 10.112.17.39 with SMTP id l7mr1431099lbd.114.1425435137442; Tue, 03 Mar 2015 18:12:17 -0800 (PST) Received: from rsa-laptop.internal.lan ([217.25.229.52]) by mx.google.com with ESMTPSA id w9sm481491lae.35.2015.03.03.18.12.16 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Mar 2015 18:12:16 -0800 (PST) From: Sergey Ryazanov To: linux-wireless@vger.kernel.org Cc: Jiri Slaby , Nick Kossifidis , "Luis R. Rodriguez" Subject: [PATCH 1/2] ath5k: channel change fix Date: Wed, 4 Mar 2015 05:12:10 +0300 Message-Id: <1425435131-12701-2-git-send-email-ryazanov.s.a@gmail.com> X-Mailer: git-send-email 2.0.4 In-Reply-To: <1425435131-12701-1-git-send-email-ryazanov.s.a@gmail.com> References: <1425435131-12701-1-git-send-email-ryazanov.s.a@gmail.com> Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, T_DKIM_INVALID, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP ath5k updates the channel pointer and after that it stops the Rx logic and apply channel to HW. In case of channel switch, such sequence creates a small window when a frame, which is received on the old channel is considered as a frame received on the new one. The most notable consequence of this situation occurs during the switch from 2 GHz band (CCK+OFDM) to the 5GHz band (OFDM-only). Frame received with CCK rate, e.g. beacon received at the 1mbps, causes the following warning: WARNING: at ath5k/base.c:589 ath5k_tasklet_rx+0x318/0x6ec [ath5k]() invalid hw_rix: 1a [..] Call Trace: [<802656a8>] show_stack+0x48/0x70 [<802dd92c>] warn_slowpath_common+0x88/0xbc [<802dd98c>] warn_slowpath_fmt+0x2c/0x38 [<81b51be8>] ath5k_tasklet_rx+0x318/0x6ec [ath5k] [<8028ac64>] tasklet_action+0x8c/0xf0 [<80075804>] __do_softirq+0x180/0x32c [<80196ce8>] irq_exit+0x54/0x70 [<80041848>] ret_from_irq+0x0/0x4 [<80182fdc>] ioread32+0x4/0xc [<81b4c42c>] ath5k_hw_set_sleep_clock+0x2ec/0x474 [ath5k] [<81b4cf28>] ath5k_hw_reset+0x50/0xeb8 [ath5k] [<81b50900>] ath5k_reset+0xd4/0x310 [ath5k] [<81b557e8>] ath5k_config+0x4c/0x104 [ath5k] [<80d01770>] ieee80211_hw_config+0x2f4/0x35c [mac80211] [<80d09aa8>] ieee80211_scan_work+0x2e4/0x414 [mac80211] [<8022c3f4>] process_one_work+0x28c/0x400 [<802df8f8>] worker_thread+0x258/0x3c0 [<801b5710>] kthread+0xe0/0xec [<800418a8>] ret_from_kernel_thread+0x14/0x1c The easiest way to reproduce this warning is to run scan with dualband NIC in noisy environments, when the channel 11 runs multiple APs. In my tests if the APs num >= 12, the warning appears in the first few seconds of scanning. In order to fix this, the Rx disable code moved to a higher level and placed before the channel pointer update. This is also makes the code a bit more symmetrical, since we disable and enable the Rx in the same function. In fact, at the pointer update time new frames should not appear, because interrupt generation at this point should already be disabled. The next patch should address this issue. CC: Jiri Slaby CC: Nick Kossifidis CC: Luis R. Rodriguez Reported-by: Christophe Prevotaux Tested-by: Christophe Prevotaux Tested-by: Eric Bree Signed-off-by: Sergey Ryazanov --- drivers/net/wireless/ath/ath5k/base.c | 24 +++++++++++++++++++++--- drivers/net/wireless/ath/ath5k/reset.c | 24 ------------------------ 2 files changed, 21 insertions(+), 27 deletions(-) diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c index bc9cb35..34b2f15 100644 --- a/drivers/net/wireless/ath/ath5k/base.c +++ b/drivers/net/wireless/ath/ath5k/base.c @@ -2858,7 +2858,7 @@ ath5k_reset(struct ath5k_hw *ah, struct ieee80211_channel *chan, { struct ath_common *common = ath5k_hw_common(ah); int ret, ani_mode; - bool fast; + bool fast = chan && modparam_fastchanswitch ? 1 : 0; ATH5K_DBG(ah, ATH5K_DEBUG_RESET, "resetting\n"); @@ -2876,11 +2876,29 @@ ath5k_reset(struct ath5k_hw *ah, struct ieee80211_channel *chan, * so we should also free any remaining * tx buffers */ ath5k_drain_tx_buffs(ah); + + /* Stop PCU */ + ath5k_hw_stop_rx_pcu(ah); + + /* Stop DMA + * + * Note: If DMA didn't stop continue + * since only a reset will fix it. + */ + ret = ath5k_hw_dma_stop(ah); + + /* RF Bus grant won't work if we have pending + * frames + */ + if (ret && fast) { + ATH5K_DBG(ah, ATH5K_DEBUG_RESET, + "DMA didn't stop, falling back to normal reset\n"); + fast = false; + } + if (chan) ah->curchan = chan; - fast = ((chan != NULL) && modparam_fastchanswitch) ? 1 : 0; - ret = ath5k_hw_reset(ah, ah->opmode, ah->curchan, fast, skip_pcu); if (ret) { ATH5K_ERR(ah, "can't reset hardware (%d)\n", ret); diff --git a/drivers/net/wireless/ath/ath5k/reset.c b/drivers/net/wireless/ath/ath5k/reset.c index b9b651e..99e62f9 100644 --- a/drivers/net/wireless/ath/ath5k/reset.c +++ b/drivers/net/wireless/ath/ath5k/reset.c @@ -1169,30 +1169,6 @@ ath5k_hw_reset(struct ath5k_hw *ah, enum nl80211_iftype op_mode, if (ah->ah_version == AR5K_AR5212) ath5k_hw_set_sleep_clock(ah, false); - /* - * Stop PCU - */ - ath5k_hw_stop_rx_pcu(ah); - - /* - * Stop DMA - * - * Note: If DMA didn't stop continue - * since only a reset will fix it. - */ - ret = ath5k_hw_dma_stop(ah); - - /* RF Bus grant won't work if we have pending - * frames */ - if (ret && fast) { - ATH5K_DBG(ah, ATH5K_DEBUG_RESET, - "DMA didn't stop, falling back to normal reset\n"); - fast = false; - /* Non fatal, just continue with - * normal reset */ - ret = 0; - } - mode = channel->hw_value; switch (mode) { case AR5K_MODE_11A: