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=-9.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 62E9DC00A89 for ; Fri, 30 Oct 2020 22:06:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E21B12087E for ; Fri, 30 Oct 2020 22:06:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="E9guYytS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725889AbgJ3WGg (ORCPT ); Fri, 30 Oct 2020 18:06:36 -0400 Received: from m42-4.mailgun.net ([69.72.42.4]:23688 "EHLO m42-4.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725830AbgJ3WGg (ORCPT ); Fri, 30 Oct 2020 18:06:36 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1604095596; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=lGkiIC6aCmxVlnP+kS5/v1V4Xiy5BR0zSGoVebzuAD4=; b=E9guYytSgnxz+YfFRC4FZjFKfdVJlcOjC8LR5JWa5UuOByoIzCdTTfTHPmblsP3cFlxheByw r88fkmC8HN/a1VEza1O/Dejstv/5JlaXHnqDg78hg5W7NSwOCvKrL16Pb7BWyy/P0ORgX0xb IMqCOsIf2fmJkyaSpYzyI3O2aLM= X-Mailgun-Sending-Ip: 69.72.42.4 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n07.prod.us-east-1.postgun.com with SMTP id 5f9c8e6bd306da06745d2c2d (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Fri, 30 Oct 2020 22:06:35 GMT Sender: khsieh=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id D21C6C43382; Fri, 30 Oct 2020 22:06:34 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: khsieh) by smtp.codeaurora.org (Postfix) with ESMTPSA id F1979C433C8; Fri, 30 Oct 2020 22:06:33 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 30 Oct 2020 15:06:33 -0700 From: khsieh@codeaurora.org To: Stephen Boyd Cc: robdclark@gmail.com, sean@poorly.run, tanmay@codeaurora.org, abhinavk@codeaurora.org, aravindh@codeaurora.org, airlied@linux.ie, daniel@ffwll.ch, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/msm/dp: skip checking LINK_STATUS_UPDATED bit In-Reply-To: <160323215566.884498.14018580767640192186@swboyd.mtv.corp.google.com> References: <20201020165959.7441-1-khsieh@codeaurora.org> <160323215566.884498.14018580767640192186@swboyd.mtv.corp.google.com> Message-ID: <546018237be3f05b4eb33c916ed1d939@codeaurora.org> X-Sender: khsieh@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-10-20 15:15, Stephen Boyd wrote: > Quoting Kuogee Hsieh (2020-10-20 09:59:59) >> No need to check LINK_STATuS_UPDATED bit before > > LINK_STATUS_UPDATED? > >> return 6 bytes of link status during link training. > > Why? > >> This patch also fix phy compliance test link rate >> conversion error. > > How? > >> >> Signed-off-by: Kuogee Hsieh >> --- > > Any Fixes: tag? > >> drivers/gpu/drm/msm/dp/dp_ctrl.c | 20 ++++++-------------- >> drivers/gpu/drm/msm/dp/dp_link.c | 24 +++++++++++------------- >> 2 files changed, 17 insertions(+), 27 deletions(-) >> >> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c >> b/drivers/gpu/drm/msm/dp/dp_ctrl.c >> index 6bdaec778c4c..76e891c91c6e 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c >> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c >> @@ -1061,23 +1061,15 @@ static bool dp_ctrl_train_pattern_set(struct >> dp_ctrl_private *ctrl, >> static int dp_ctrl_read_link_status(struct dp_ctrl_private *ctrl, >> u8 *link_status) >> { >> - int len = 0; >> - u32 const offset = DP_LANE_ALIGN_STATUS_UPDATED - >> DP_LANE0_1_STATUS; >> - u32 link_status_read_max_retries = 100; >> - >> - while (--link_status_read_max_retries) { >> - len = drm_dp_dpcd_read_link_status(ctrl->aux, >> - link_status); >> - if (len != DP_LINK_STATUS_SIZE) { >> - DRM_ERROR("DP link status read failed, err: >> %d\n", len); >> - return len; >> - } >> + int ret = 0, len; >> >> - if (!(link_status[offset] & DP_LINK_STATUS_UPDATED)) >> - return 0; >> + len = drm_dp_dpcd_read_link_status(ctrl->aux, link_status); >> + if (len != DP_LINK_STATUS_SIZE) { >> + DRM_ERROR("DP link status read failed, err: %d\n", >> len); >> + ret = len; > > Could this be positive if the len is greater than 0 but not > DP_LINK_STATUS_SIZE? Maybe the check should be len < 0? We certainly > don't want to return some smaller size from this function, right? > no, it should be exactly the byte number requested to read. otherwise, it should be failed and will re read at next run. >> } >> >> - return -ETIMEDOUT; >> + return ret; >> } >> >> static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl, >> diff --git a/drivers/gpu/drm/msm/dp/dp_link.c >> b/drivers/gpu/drm/msm/dp/dp_link.c >> index c811da515fb3..58d65daae3b3 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_link.c >> +++ b/drivers/gpu/drm/msm/dp/dp_link.c >> @@ -773,7 +773,8 @@ static int >> dp_link_process_link_training_request(struct dp_link_private *link) >> link->request.test_lane_count); >> >> link->dp_link.link_params.num_lanes = >> link->request.test_lane_count; >> - link->dp_link.link_params.rate = link->request.test_link_rate; >> + link->dp_link.link_params.rate = >> + >> drm_dp_bw_code_to_link_rate(link->request.test_link_rate); > > Why are we storing bw_code in test_link_rate? This looks very > confusing. Test_link_rate contains link rate from dpcd read. it need to be convert to real rate by timing 2.7Mb before start phy compliance test. > >> >> return 0; >> }