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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 93EFCC4320A for ; Fri, 20 Aug 2021 17:26:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A44C610A3 for ; Fri, 20 Aug 2021 17:26:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234367AbhHTR1B (ORCPT ); Fri, 20 Aug 2021 13:27:01 -0400 Received: from mga17.intel.com ([192.55.52.151]:61220 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230151AbhHTR1A (ORCPT ); Fri, 20 Aug 2021 13:27:00 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10082"; a="197066296" X-IronPort-AV: E=Sophos;i="5.84,338,1620716400"; d="scan'208";a="197066296" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Aug 2021 10:26:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.84,338,1620716400"; d="scan'208";a="463445143" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.171]) by orsmga007.jf.intel.com with SMTP; 20 Aug 2021 10:26:15 -0700 Received: by stinkbox (sSMTP sendmail emulation); Fri, 20 Aug 2021 20:26:14 +0300 Date: Fri, 20 Aug 2021 20:26:14 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Kai-Heng Feng Cc: jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, David Airlie , Daniel Vetter , Imre Deak , Uma Shankar , Manasi Navare , Ankit Nautiyal , =?iso-8859-1?Q?Jos=E9?= Roberto de Souza , Sean Paul , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] drm/i915/dp: Use max params for panels < eDP 1.4 Message-ID: References: <20210820075301.693099-1-kai.heng.feng@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210820075301.693099-1-kai.heng.feng@canonical.com> X-Patchwork-Hint: comment Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 20, 2021 at 03:52:59PM +0800, Kai-Heng Feng wrote: > Users reported that after commit 2bbd6dba84d4 ("drm/i915: Try to use > fast+narrow link on eDP again and fall back to the old max strategy on > failure"), the screen starts to have wobbly effect. > > Commit a5c936add6a2 ("drm/i915/dp: Use slow and wide link training for > everything") doesn't help either, that means the affected eDP 1.2 panels > only work with max params. > > So use max params for panels < eDP 1.4 as Windows does to solve the > issue. > > v3: > - Do the eDP rev check in intel_edp_init_dpcd() > > v2: > - Check eDP 1.4 instead of DPCD 1.1 to apply max params > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3714 > Fixes: 2bbd6dba84d4 ("drm/i915: Try to use fast+narrow link on eDP again and fall back to the old max strategy on failure") > Fixes: a5c936add6a2 ("drm/i915/dp: Use slow and wide link training for everything") > Suggested-by: Ville Syrjälä > Signed-off-by: Kai-Heng Feng Slapped a cc:stable on it and pushed to drm-intel-next. Thanks. > --- > drivers/gpu/drm/i915/display/intel_dp.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c > index 75d4ebc669411..e0dbd35ae7bc0 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -2445,11 +2445,14 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp) > */ > if (drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_DPCD_REV, > intel_dp->edp_dpcd, sizeof(intel_dp->edp_dpcd)) == > - sizeof(intel_dp->edp_dpcd)) > + sizeof(intel_dp->edp_dpcd)) { > drm_dbg_kms(&dev_priv->drm, "eDP DPCD: %*ph\n", > (int)sizeof(intel_dp->edp_dpcd), > intel_dp->edp_dpcd); > > + intel_dp->use_max_params = intel_dp->edp_dpcd[0] < DP_EDP_14; > + } > + > /* > * This has to be called after intel_dp->edp_dpcd is filled, PSR checks > * for SET_POWER_CAPABLE bit in intel_dp->edp_dpcd[1] > -- > 2.32.0 -- Ville Syrjälä Intel