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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 607CBC4829A for ; Tue, 13 Feb 2024 18:15:12 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B6AFB10E5AA; Tue, 13 Feb 2024 18:15:11 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="KcokuQLo"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) by gabe.freedesktop.org (Postfix) with ESMTPS id F12BA10E5AA for ; Tue, 13 Feb 2024 18:15:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1707848111; x=1739384111; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=EPr+atZLHrSGR8qhgaZxpXU6B17yfxeRKWK3fnAua4o=; b=KcokuQLoy59QYv/5rxR22Mlh/4WEjCISDTx+B0jgOiNU70BotUsKxGkv EO0AQ0snFADjf+x/yZ7Zj2PZ0FBG+7YsySp6u2kE/JAvdQQ5N15XzazaG 6fOo5n3zjqJyGYLPncHqhZFuHCM9RbzfpgT/3XpWohGgwraOAoHp6dfM+ wIvsnY9S1SO99vqs8tROydW3yWAgp4H2C6sUUUuEanNixJV0CCTxYfMws he0a+sxNgorIt1sZEWkhWDnvdj+ZrVc2s+Kr2w283BTi+12NtKi2GQp33 6/OiHCyZ2M0qKaCCzkAt0CNA9EbgvtC9P2Hw7rAB5xp7F2FG7qcJmnaIW w==; X-IronPort-AV: E=McAfee;i="6600,9927,10982"; a="27315268" X-IronPort-AV: E=Sophos;i="6.06,157,1705392000"; d="scan'208";a="27315268" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Feb 2024 10:15:10 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.06,157,1705392000"; d="scan'208";a="7708504" Received: from snasibli-mobl2.ccr.corp.intel.com (HELO localhost) ([10.252.44.50]) by orviesa004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Feb 2024 10:15:07 -0800 From: Jani Nikula To: Arun R Murthy , intel-gfx@lists.freedesktop.org Cc: imre.deak@intel.com, ville.syrjala@intel.com, uma.shankar@intel.com, Arun R Murthy Subject: Re: [RFC 4/4] drm/i915/display/dp: On LT failure retry LT In-Reply-To: <20240206104759.2079133-5-arun.r.murthy@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20240206104759.2079133-1-arun.r.murthy@intel.com> <20240206104759.2079133-5-arun.r.murthy@intel.com> Date: Tue, 13 Feb 2024 20:15:04 +0200 Message-ID: <87v86s6xjr.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, 06 Feb 2024, Arun R Murthy wrote: > On link training failure retry link training with a lesser link > rate/lane count as specified in the DP spec. > > Signed-off-by: Arun R Murthy > --- > drivers/gpu/drm/i915/display/intel_ddi.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c > index ed7620e7f763..29d785a4b904 100644 > --- a/drivers/gpu/drm/i915/display/intel_ddi.c > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c > @@ -2502,6 +2502,7 @@ static void mtl_ddi_pre_enable_dp(struct intel_atomic_state *state, > crtc_state->port_clock, > crtc_state->lane_count); > > +retry: > /* > * We only configure what the register value will be here. Actual > * enabling happens during link training farther down. > @@ -2586,7 +2587,14 @@ static void mtl_ddi_pre_enable_dp(struct intel_atomic_state *state, > * Pattern, wait for 5 idle patterns (DP_TP_STATUS Min_Idles_Sent) > * (timeout after 800 us) > */ > - intel_dp_start_link_train(intel_dp, crtc_state); > + if (!intel_dp_start_link_train(intel_dp, crtc_state)) { > + /* Link Training failed, retain */ > + intel_dp->link_trained = false; > + intel_dp_stop_link_train(intel_dp, crtc_state); > + encoder->post_disable(state, encoder, > + crtc_state, conn_state); > + goto retry; > + } As said, the retry needs to go via userspace. BR, Jani. > > /* 6.n Set DP_TP_CTL link training to Normal */ > if (!is_trans_port_sync_mode(crtc_state)) -- Jani Nikula, Intel