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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 33F35CA9EA0 for ; Fri, 18 Oct 2019 18:03:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1062F21D7C for ; Fri, 18 Oct 2019 18:03:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="daWXD1ny" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2505659AbfJRSDn (ORCPT ); Fri, 18 Oct 2019 14:03:43 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:40721 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727054AbfJRSDn (ORCPT ); Fri, 18 Oct 2019 14:03:43 -0400 Received: by mail-pf1-f194.google.com with SMTP id x127so4343951pfb.7 for ; Fri, 18 Oct 2019 11:03:41 -0700 (PDT) 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=8/ZS+906/9FcfZAV3qaij45dj3UK3E6lm1Y4pz31ip8=; b=daWXD1nygLkP7A5y9K7cowvo3WWYzDRQR4UTxSWALIoMmSexkvrCrGbeludebonnvR lSrvphIFIfHSlvohBF/QW0GdN/0BsjuoIvIcxsQuANTT4o9vsQRiUUtH812PSNUysuQE qTp+cenvmSFjrNCkI12Nt/5rIi7qyfyNrhRto= 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=8/ZS+906/9FcfZAV3qaij45dj3UK3E6lm1Y4pz31ip8=; b=m+NPcOu5R903IQeihBxZiUtP0gckvnTMi/hK3G5VaQyWAYBSgqqnIYskp7pUNrR6bU HXfY2ZFkLFq1eFt0Z2YdBuzhBMaLwDjT3xnnacO+nvxGmTbfdo0Ku9buAaHgwODeUv4T st6U5Yfu6F21b0TALrHqWdse+dJDHRIk3kcafWE1XbZ8vRGttX66gcGwC4Dl/lkKYe99 stAiK8qHgdyGLr/aSKys2eICMKnSYxdjPeFAmJUGAbCp7gOnxi0IFGk0bvLZsyxTNRHV T5ggdcrVyJbvF2YZpL2sBqKxptbJsPJym0kB6p1Or9Ld4zCLMVaoKcobwr84//CEU5A1 9Vwg== X-Gm-Message-State: APjAAAUv6wtCEU1u5pW7i/WEY4goTl5qiSSJTcdClKrRIqaoZz1PuM/p n3R7k6A4TPh2K25W/Cc/L7+qBw== X-Google-Smtp-Source: APXvYqzPFGfktG3Py1x/vmEI6cC7z8QO39KHafDjtPfHiiUUnrPmfUmcK6PTAQJBIhon1QiV/qEFuA== X-Received: by 2002:a63:c901:: with SMTP id o1mr11394460pgg.66.1571421821320; Fri, 18 Oct 2019 11:03:41 -0700 (PDT) Received: from localhost ([2620:15c:202:1:4fff:7a6b:a335:8fde]) by smtp.gmail.com with ESMTPSA id y66sm7424489pgy.23.2019.10.18.11.03.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 18 Oct 2019 11:03:40 -0700 (PDT) Date: Fri, 18 Oct 2019 11:03:39 -0700 From: Matthias Kaehlcke To: Jeffrey Hugo Cc: marcel@holtmann.org, johan.hedberg@gmail.com, c-hbandi@codeaurora.org, bgodavar@codeaurora.org, linux-bluetooth@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Bluetooth: hci_qca: Add delay for wcn3990 stability Message-ID: <20191018180339.GQ87296@google.com> References: <20191017212955.6266-1-jeffrey.l.hugo@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191017212955.6266-1-jeffrey.l.hugo@gmail.com> 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 Thu, Oct 17, 2019 at 02:29:55PM -0700, Jeffrey Hugo wrote: > On the msm8998 mtp, the response to the baudrate change command is never > received. On the Lenovo Miix 630, the response to the baudrate change > command is corrupted - "Frame reassembly failed (-84)". > > Adding a 50ms delay before re-enabling flow to receive the baudrate change > command response from the wcn3990 addesses both issues, and allows > bluetooth to become functional. >From my earlier debugging on sdm845 I don't think this is what happens. The problem is that the wcn3990 sends the response to the baudrate change command using the new baudrate, while the UART on the SoC still operates with the prior speed (for details see 2faa3f15fa2f ("Bluetooth: hci_qca: wcn3990: Drop baudrate change vendor event")) IIRC the 50ms delay causes the HCI core to discard the received data, which is why the "Frame reassembly failed" message disappears, not because the response was received. In theory commit 78e8fa2972e5 ("Bluetooth: hci_qca: Deassert RTS while baudrate change command") should have fixed those messages, do you know if CTS/RTS are connected on the Bluetooth UART of the Lenovo Miix 630?