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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 715C3C6FA83 for ; Mon, 12 Sep 2022 18:41:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230483AbiILSlE (ORCPT ); Mon, 12 Sep 2022 14:41:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51898 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231269AbiILSkc (ORCPT ); Mon, 12 Sep 2022 14:40:32 -0400 Received: from mail-lf1-x133.google.com (mail-lf1-x133.google.com [IPv6:2a00:1450:4864:20::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 344FDB862 for ; Mon, 12 Sep 2022 11:39:55 -0700 (PDT) Received: by mail-lf1-x133.google.com with SMTP id s6so5098048lfo.7 for ; Mon, 12 Sep 2022 11:39:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date; bh=rBnJnt9s2rBQ5GOGLgcOmWi4AblijZUFNNPxpAcR8p4=; b=J9+bQLzRFi1I3i88LXpTbLRCgdIQBftNKkAd1h6SwYtLkKr2xyJy8y9zZ+N5jtJcT3 kWWLrDtZQ8Hre+9JIpCbWoV256aSDJFajhYwBlvv9U4SK2tsPwUTckEidDelcn06Tg0R Ev6kh9Yc3xYhLAFKWPyAImkb8MCJbZOgPLNQpxRu4T5oYw2IN5Sq8xgjeaojnh7uT6Z6 TCWxL0ah2r1gIvmh7sIJ9lZw5Gdq/nce1nXDE8kWKBQBGbwsWF09qoKCZy1X99mdkzyo GmUC1uaNXGpYV3IMCCOdgUnoVsPJwI84BCYhGGJnMWpI2fuZsEKgC2JRo4jSGpTWJXe6 6ocg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date; bh=rBnJnt9s2rBQ5GOGLgcOmWi4AblijZUFNNPxpAcR8p4=; b=dKidGeP3ZDpviic2BGM2RitIiasmB0snCaR961exfTCzq1ondcJKEQaHwWVFdqg64q dduhbZlhoKsHPX4BqlOxTiV2NsmcOu7aio0va3l0iJ4ojipQBBGUSDn7w/bacSboLkgW mfv+u2y38xzruDemgpCN7ueFT9hmZK1ytpqQZILH7ezF75Bo3FRFR1jRrMJ1yCPdNG6D 12TptuaUb+b40YDiBQxcTj5zZHu2VTHoQsNek0SCGHT1mgPYz/xk94B5M9nf4OaJdkxP 5tJOPVFfNLS1Qr5jzJm1XVxFtQaU9urxZnBce/Xbd5BixVxDK9AjkBPquUE3DOaBmN79 xEZQ== X-Gm-Message-State: ACgBeo3KN+iHf3FKFQgi71Gh1wgJIm9VFqh3UOO6ZHoSIMPmPX6uS3Mb fECH7gF62gHDKq4BsoaJq/lSiLGTc9EQ7w== X-Google-Smtp-Source: AA6agR4LiOmbWOuOJGJC8fm/foifEisyJZxwjrlZUaQk4zMBMjnfO6L3aFriO6IIG/ht918aPzdqtg== X-Received: by 2002:a05:6512:ac3:b0:498:f076:6281 with SMTP id n3-20020a0565120ac300b00498f0766281mr6829018lfu.68.1663007993481; Mon, 12 Sep 2022 11:39:53 -0700 (PDT) Received: from [192.168.1.211] ([37.153.55.125]) by smtp.gmail.com with ESMTPSA id d4-20020ac25444000000b00494a2a0f6cfsm1205964lfn.183.2022.09.12.11.39.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 12 Sep 2022 11:39:53 -0700 (PDT) Message-ID: <0f381285-860f-aaa2-2ae7-834608d0b4e8@linaro.org> Date: Mon, 12 Sep 2022 21:39:52 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.1 Subject: Re: [PATCH v5 1/3] drm/msm/dp: cleared DP_DOWNSPREAD_CTRL register before start link training Content-Language: en-GB To: Kuogee Hsieh , dri-devel@lists.freedesktop.org, robdclark@gmail.com, sean@poorly.run, swboyd@chromium.org, dianders@chromium.org, vkoul@kernel.org, daniel@ffwll.ch, airlied@linux.ie, agross@kernel.org, bjorn.andersson@linaro.org Cc: quic_abhinavk@quicinc.com, quic_sbillaka@quicinc.com, freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org References: <1662999830-13916-1-git-send-email-quic_khsieh@quicinc.com> <1662999830-13916-2-git-send-email-quic_khsieh@quicinc.com> From: Dmitry Baryshkov In-Reply-To: <1662999830-13916-2-git-send-email-quic_khsieh@quicinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/09/2022 19:23, Kuogee Hsieh wrote: > DOWNSPREAD_CTRL (0x107) shall be cleared to 0 upon power-on reset or an > upstream device disconnect. This patch will enforce this rule by always > cleared DOWNSPREAD_CTRL register to 0 before start link training. At rare > case that DP MSA timing parameters may be mis-interpreted by the sink > which causes audio sampling rate be calculated wrongly and cause audio > did not work at sink if DOWNSPREAD_CTRL register is not cleared to 0. > > Changes in v2: > 1) fix spelling at commit text > 2) merge ssc variable into encoding[0] > > Changes in v3: > -- correct spelling of DOWNSPREAD_CTRL > -- replace err with len of ssize_t > > Changes in v4: > -- split into 2 patches > > Fixes: 154b5a7da0fd ("drm/msm/dp: add displayPort driver support") > Signed-off-by: Kuogee Hsieh > --- > drivers/gpu/drm/msm/dp/dp_ctrl.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c > index ab6aa13..2c74c59 100644 > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c > @@ -1245,8 +1245,7 @@ static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl, > { > int ret = 0; > const u8 *dpcd = ctrl->panel->dpcd; > - u8 encoding = DP_SET_ANSI_8B10B; > - u8 ssc; > + u8 encoding[] = { 0, DP_SET_ANSI_8B10B }; > u8 assr; > struct dp_link_info link_info = {0}; > > @@ -1258,13 +1257,11 @@ static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl, > > dp_aux_link_configure(ctrl->aux, &link_info); > > - if (drm_dp_max_downspread(dpcd)) { > - ssc = DP_SPREAD_AMP_0_5; > - drm_dp_dpcd_write(ctrl->aux, DP_DOWNSPREAD_CTRL, &ssc, 1); > - } > + if (drm_dp_max_downspread(dpcd)) > + encoding[0] |= DP_SPREAD_AMP_0_5; It would be simpler to call drm_dp_dpcd_write(ssc, DP_DOWNSPREAD_CTRL, 1) unconditionally here. You won't have to change the encoding/DP_MAIN_LINK_CHANNEL_CODING_SET/etc. > > - drm_dp_dpcd_write(ctrl->aux, DP_MAIN_LINK_CHANNEL_CODING_SET, > - &encoding, 1); > + /* config DOWNSPREAD_CTRL and MAIN_LINK_CHANNEL_CODING_SET */ > + drm_dp_dpcd_write(ctrl->aux, DP_DOWNSPREAD_CTRL, encoding, 2); > > if (drm_dp_alternate_scrambler_reset_cap(dpcd)) { > assr = DP_ALTERNATE_SCRAMBLER_RESET_ENABLE; -- With best wishes Dmitry