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=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=unavailable 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 BB193C43387 for ; Thu, 17 Jan 2019 10:28:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 86AF42054F for ; Thu, 17 Jan 2019 10:28:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="WLlFwYtX"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="gBkjD5R6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727988AbfAQK1z (ORCPT ); Thu, 17 Jan 2019 05:27:55 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:39288 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727929AbfAQK1y (ORCPT ); Thu, 17 Jan 2019 05:27:54 -0500 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 6E63460A0A; Thu, 17 Jan 2019 10:27:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1547720873; bh=NOsk1mAdMP9C98CozzoBaA3CYvF+HcfMMSA7Tf0HRMY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=WLlFwYtXWMuJW042vYCGtfcTeQD5PgxPXs6GjPsJrwbZrn6iKNqTSXNxa6t6b5hUT TylTSNt2KqaYnzsjFVp5dCNXGrSAZ/2WGpnuUCMv0Bu1sjZbaNMoyzF438MN3lWCTw K1RCilKFoWrpNyqSMcvhJMluLkkUU9Nwo0xdFrHc= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 2EBB460A08; Thu, 17 Jan 2019 10:27:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1547720869; bh=NOsk1mAdMP9C98CozzoBaA3CYvF+HcfMMSA7Tf0HRMY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=gBkjD5R6AHPCWR7OlblBly/tJY6Vr3jjzsJkos6UICNvyKMT6+mB/op78pbVa6kjS snlDAHhpNoZkSXKTTQxwcfqiTWjU4D3XDZRup/590Q7Sn1SZV7qoMiQxHaa7KvgHBq fLn9YMsMTaOhBK2bUC0mAXA6+knZj6b1JlssqhGs= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Thu, 17 Jan 2019 15:57:48 +0530 From: Balakrishna Godavarthi To: Matthias Kaehlcke 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 In-Reply-To: <20190116230801.GT261387@google.com> References: <20190116114603.500-1-bgodavar@codeaurora.org> <20190116114603.500-4-bgodavar@codeaurora.org> <20190116230801.GT261387@google.com> Message-ID: <5b507ee20e9e4ba022334433aa2f3691@codeaurora.org> X-Sender: bgodavar@codeaurora.org User-Agent: Roundcube Webmail/1.2.5 Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org On 2019-01-17 04:38, Matthias Kaehlcke wrote: > 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); > + [Bala]: Thanks for catch this. yes you are rite, we will have an byte queued in the skb. will update with the lock. > host_set_baudrate(hu, 2400); > qca_send_power_pulse(hu, QCA_WCN3990_POWEROFF_PULSE); > qca_power_setup(hu, false); > > Cheers > > Matthias -- Regards Balakrishna.