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=-9.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 B5646C43387 for ; Wed, 16 Jan 2019 23:08:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7D5E620675 for ; Wed, 16 Jan 2019 23:08:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="m3/DMABm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388101AbfAPXIE (ORCPT ); Wed, 16 Jan 2019 18:08:04 -0500 Received: from mail-pf1-f196.google.com ([209.85.210.196]:46872 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388099AbfAPXIE (ORCPT ); Wed, 16 Jan 2019 18:08:04 -0500 Received: by mail-pf1-f196.google.com with SMTP id c73so3777185pfe.13 for ; Wed, 16 Jan 2019 15:08:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=cNtoC5c+2YT8QEQeFenQ+Gr8RS5xW2AkUGFuDXVHCZY=; b=m3/DMABmDqIGq6dA1cgQZV76a4RAkojPOq/bhMtJ7HKfIF//gvaQGe/isvAKiLeYns DdcCfE/MHSstsI9xpXsNH62OuCeFtPXIW/Cwi3SQfoQm+43LmS6/A3SVzEmgByn5XxkX 7E1E9KmvkNTHgAFLtyp5+4DyzNqqQrLxYI1AE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=cNtoC5c+2YT8QEQeFenQ+Gr8RS5xW2AkUGFuDXVHCZY=; b=QJpjerKzRNX9tVVHRJiZL+79Q2dwx9rFCtXLffnoXMwGJZmnX1UyWqdov1Pq0yR5Sk xBEI7M1sOwfzdxYtO4ZiJN9fVNyji6qVgSVlVbt+v19Sd+8y+HCsMilBLqGO1dN9yEqS K/2JXUkwLdUwO3klWjVnsTBZxU1dsRIx4rQ7KnlFOzrxL6KSvOZxDy6GsEUc+PgDz/ae ydGXGeloEGf0dwAtuoDHKXWxb3mXa0gxE/vkBO2KeCeRmx+PqJIFWmrrMmtkJz019RCO rNYQi6MfF7wjS2h2Dt/Gjozq0814It24OdmqN+xMq8RNuXtBtxvtgoHQuk5e/84+fGM2 Glng== X-Gm-Message-State: AJcUukfoT2WhC6FMRdR9SfQDFndAFOzKNXmWiO4pNHefjTbM0Qs/E6Zo O9aFZyxH8wjU5f9paxLr6SDfng== X-Google-Smtp-Source: ALg8bN6Am5nT8i39NRPY8BzcfaGxa+8CSRc0ja/otbCRzYOL62H+zmoWB5whiwhRLwlLhC8rtw9sqA== X-Received: by 2002:a63:b543:: with SMTP id u3mr11106658pgo.420.1547680083440; Wed, 16 Jan 2019 15:08:03 -0800 (PST) Received: from localhost ([2620:15c:202:1:75a:3f6e:21d:9374]) by smtp.gmail.com with ESMTPSA id x7sm7899802pga.68.2019.01.16.15.08.02 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 16 Jan 2019 15:08:02 -0800 (PST) Date: Wed, 16 Jan 2019 15:08:01 -0800 From: Matthias Kaehlcke To: Balakrishna Godavarthi Cc: marcel@holtmann.org, johan.hedberg@gmail.com, linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org, hemantg@codeaurora.org, linux-arm-msm@vger.kernel.org Subject: Re: [PATCH v8 3/3] Bluetooth: hci_qca: Disable IBS state machine and flush Tx buffer Message-ID: <20190116230801.GT261387@google.com> References: <20190116114603.500-1-bgodavar@codeaurora.org> <20190116114603.500-4-bgodavar@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190116114603.500-4-bgodavar@codeaurora.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org On Wed, Jan 16, 2019 at 05:16:03PM +0530, Balakrishna Godavarthi wrote: > During hci down we observed IBS sleep commands are queued in the Tx > buffer and hci_uart_write_work is sending data to the chip which is > not required as the chip is powered off. This patch will disable IBS > and flush the Tx buffer before we turn off the chip. > > Signed-off-by: Balakrishna Godavarthi > --- > drivers/bluetooth/hci_qca.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c > index 7e4afcf40da2..7330ba71ada4 100644 > --- a/drivers/bluetooth/hci_qca.c > +++ b/drivers/bluetooth/hci_qca.c > @@ -1275,6 +1275,14 @@ static const struct qca_vreg_data qca_soc_data = { > > static void qca_power_shutdown(struct hci_uart *hu) > { > + struct qca_data *qca = hu->priv; > + > + /* From this point we go into power off state. But serial port is > + * still open, stop queueing the IBS data and flush all the buffered > + * data in skb's. > + */ > + clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags); > + qca_flush(hu); > host_set_baudrate(hu, 2400); > qca_send_power_pulse(hu, QCA_WCN3990_POWEROFF_PULSE); > qca_power_setup(hu, false); Due to a race-condition there could be an IBS sleep command queued even after clearing the bit and flushing the queue. In qca_enqueue() we have this: static int qca_enqueue(struct hci_uart *hu, struct sk_buff *skb) { ... /* Don't go to sleep in middle of patch download or * Out-Of-Band(GPIOs control) sleep is selected. */ if (!test_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags)) { skb_queue_tail(&qca->txq, skb); return 0; } spin_lock_irqsave(&qca->hci_ibs_lock, flags); } With process X executing qca_power_shutdown() and process Y running qca_enqueue() this could happen: [X] test_bit(STATE_IN_BAND_SLEEP_ENABLED) => set [Y] clear_bit(STATE_IN_BAND_SLEEP_ENABLED) [Y] qca_flush(hu); [X] skb_queue_tail(&qca->txq, skb); The following should fix this race: --- a/drivers/bluetooth/hci_qca.c +++ b/drivers/bluetooth/hci_qca.c @@ -770,16 +770,17 @@ static int qca_enqueue(struct hci_uart *hu, struct sk_buff *skb) /* Prepend skb with frame type */ memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1); + spin_lock_irqsave(&qca->hci_ibs_lock, flags); + /* Don't go to sleep in middle of patch download or * Out-Of-Band(GPIOs control) sleep is selected. */ if (!test_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags)) { skb_queue_tail(&qca->txq, skb); + spin_unlock_irqrestore(&qca->hci_ibs_lock, flags); return 0; } - spin_lock_irqsave(&qca->hci_ibs_lock, flags); - /* Act according to current state */ switch (qca->tx_ibs_state) { case HCI_IBS_TX_AWAKE: @@ -1275,13 +1276,17 @@ static const struct qca_vreg_data qca_soc_data = { static void qca_power_shutdown(struct hci_uart *hu) { struct qca_data *qca = hu->priv; + unsigned long flags; /* From this point we go into power off state. But serial port is * still open, stop queueing the IBS data and flush all the buffered * data in skb's. */ + spin_lock_irqsave(&qca->hci_ibs_lock, flags); clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags); qca_flush(hu); + spin_unlock_irqrestore(&qca->hci_ibs_lock, flags); + host_set_baudrate(hu, 2400); qca_send_power_pulse(hu, QCA_WCN3990_POWEROFF_PULSE); qca_power_setup(hu, false); Cheers Matthias