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=-8.6 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,URIBL_BLOCKED,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 CB826C282D8 for ; Fri, 1 Feb 2019 18:35:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9E797218A6 for ; Fri, 1 Feb 2019 18:35:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="V7B3jUde" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730213AbfBASfL (ORCPT ); Fri, 1 Feb 2019 13:35:11 -0500 Received: from mail-pl1-f195.google.com ([209.85.214.195]:35279 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729746AbfBASfJ (ORCPT ); Fri, 1 Feb 2019 13:35:09 -0500 Received: by mail-pl1-f195.google.com with SMTP id p8so3642367plo.2 for ; Fri, 01 Feb 2019 10:35:08 -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=1OtBkZag0N4BIBWAan1VrAJ+wFVHG96G7eftj8weeSI=; b=V7B3jUdeIGWs3B3EMjAsz1dqifM+ZwPdBbO6vo+Z1B4wyYcV6Sop4rlGMgfk8Fnf5R k7eicDtBF2705vfbwkxvwe59uFd/sj3AxwaezNBw2w3xCODsqV2aSA1kxmu6xFpTgpRk y1uKrp8reYP74EocxSjWSvzkWjb+T0eZu38vo= 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=1OtBkZag0N4BIBWAan1VrAJ+wFVHG96G7eftj8weeSI=; b=pc0ZuZ0R844tCFIudO/lR89JncO63wBSUjYL2fFzL4nyHyOja13Ebfxs4kPn5ZrJGV vn2tdig+aIg0+SjLGKioL3NLykhSwWozDjBFJmOMW2+6752O8zUOZZsRK3aur/g9bYnE lkotI3DHnQZaVJQtLe2cyl2B7Y1t70qdJTYkMBR0CrDteqn6vJEIuWBqUSxlKlrIh6U9 qelyPR+GbtnQGrAGnIHz+xKPAKyLT9hj0j/BRCsWSa/RbjtNRjW2xuAyFCV98GHHvr9G 8gQTj2P9Jrpn6ZT7oS7EuGtr1dDEr1V74/hW4FiRLZ99ILvB8wWoEdTczUz/8rp+fuvK v3cg== X-Gm-Message-State: AJcUukf/xvLyhtdwJXVOODxNh0RSLAb7wyjDv1mQyM5HYmNTOBi9z4u6 mQS4Yh6jkwMTpgsfHfqYVnFRoA== X-Google-Smtp-Source: ALg8bN7e8L+EprCeNxO/A/1jJwEbB2V3ouTtTqLmxZdJ3wHl58jHLNIZSYEjbtEtyaUUjUYNGoWbsQ== X-Received: by 2002:a17:902:2ac3:: with SMTP id j61mr40622494plb.185.1549046108047; Fri, 01 Feb 2019 10:35:08 -0800 (PST) Received: from localhost ([2620:15c:202:1:75a:3f6e:21d:9374]) by smtp.gmail.com with ESMTPSA id d16sm9027912pgj.21.2019.02.01.10.35.07 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 01 Feb 2019 10:35:07 -0800 (PST) Date: Fri, 1 Feb 2019 10:35:06 -0800 From: Matthias Kaehlcke To: Balakrishna Godavarthi Cc: marcel@holtmann.org, johan.hedberg@gmail.com, johan@kernel.org, linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org, hemantg@codeaurora.org, linux-arm-msm@vger.kernel.org Subject: Re: [PATCH v9 3/3] Bluetooth: hci_qca: Disable IBS state machine and flush Tx buffer Message-ID: <20190201183506.GR81583@google.com> References: <20190124120808.8275-1-bgodavar@codeaurora.org> <20190124120808.8275-4-bgodavar@codeaurora.org> <20190125005534.GC81583@google.com> <75923da910c43e7e5e033f4ff4360a90@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <75923da910c43e7e5e033f4ff4360a90@codeaurora.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 01, 2019 at 05:10:11PM +0530, Balakrishna Godavarthi wrote: > Hi Matthias, > > On 2019-01-25 06:25, Matthias Kaehlcke wrote: > > On Thu, Jan 24, 2019 at 05:38:08PM +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 > > > --- > > > Changes v9: > > > * added lock while disabling the IBS state machine. > > > > > > --- > > > drivers/bluetooth/hci_qca.c | 17 +++++++++++++++-- > > > 1 file changed, 15 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c > > > index 6b5bcd44e24c..99ddc35f08c6 100644 > > > --- a/drivers/bluetooth/hci_qca.c > > > +++ b/drivers/bluetooth/hci_qca.c > > > @@ -771,16 +771,17 @@ 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: > > > @@ -1273,6 +1274,18 @@ 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); > > > > I was about to add my 'Reviewed-by' tag, but I'm still left with a > > doubt. This patch certainly improves the situation by clearing the IBS > > bit and flushing the buffered data, however IIUC new data could still > > be added to the TX queue after releasing the spinlock: > > > > static int qca_enqueue(struct hci_uart *hu, struct sk_buff *skb) > > { > > ... > > > > if (!test_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags)) { > > skb_queue_tail(&qca->txq, skb); > > > > ... > > } > > > > To prevent this a boolean/bit like 'shutting_down' or similar would be > > needed (I don't think there is something common in the HCI core), > > which is set in qca_power_shutdown(). If the bit is set qca_enqueue() > > discards the data. > > > > Not sure how important this is, and I don't want to add necessarily > > more revisions to this series. If it is preferable to have an empty > > queue after shutdown maybe it can be done in a follow up patch. > > > > Thanks > > > > Matthias > > [Bala]: during shutdown Bt stack will not send any data to the Bt kernel Tx > path. > so this call may not be called. once we shutdown chip. Thanks for the clarification! I kinda expected that, but it wasn't evident to me from the core code. Reviewed-by: Matthias Kaehlcke