From patchwork Fri Jul 1 11:03:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arun R Murthy X-Patchwork-Id: 12903169 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 38CE4C433EF for ; Fri, 1 Jul 2022 11:03:39 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 991ED11ADC6; Fri, 1 Jul 2022 11:03:38 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id 65EE111ADC7 for ; Fri, 1 Jul 2022 11:03:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656673417; x=1688209417; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=baCssLcJpwX+BZp95+AC5ZWrPL8s8dO0ov2e2B3FCRA=; b=O1tl8Hi+B6wiw491Ukc6RmzTVwyT5R7LDEsgT1IQCu2JwpRSnijn38P2 unFsiqZ/OYeraLdNS6qsQe51MGWAcvVyo/vUnnDHEmQ4/tvrA312mk6j6 Rgn84PvefTVmahkAfKhtA/jxe1MYV+ZMIRE0NRKBfdLkPeGJbNG1a59h5 H+kgqUOCjwFSnrSqYN7lLU6XGTKJtUkes6kB3THbD+EfpIbHIutZsUWpW nUqN9BR9KoJEos9LQnhjEbLB64+2Z/fk6Mh0H0Ak4NLYMhnTVqIuM37MX kVXycEiZ8AY23rKj7CZ+Z1d5Dl5472N706uNyz7H3/7qpDVt5/GxdesE1 g==; X-IronPort-AV: E=McAfee;i="6400,9594,10394"; a="282656478" X-IronPort-AV: E=Sophos;i="5.92,236,1650956400"; d="scan'208";a="282656478" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2022 04:03:36 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,236,1650956400"; d="scan'208";a="718590667" Received: from srr4-3-linux-106-armuthy.iind.intel.com ([10.190.238.56]) by orsmga004.jf.intel.com with ESMTP; 01 Jul 2022 04:03:34 -0700 From: Arun R Murthy To: intel-gfx@lists.freedesktop.org Date: Fri, 1 Jul 2022 16:33:09 +0530 Message-Id: <20220701110309.1237002-1-arun.r.murthy@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220627105939.657782-1-arun.r.murthy@intel.com> References: <20220627105939.657782-1-arun.r.murthy@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCHv3] drm/i915/dp: wait on timeout before retry 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: , Cc: tprevite@gmail.com, paulo.r.zanoni@intel.com, jani.nikula@intel.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On linktraining error/timeout before retry need to wait for 400usec as per the DP CTS spec1.2 The patch with commit 74ebf294a1dd ("drm/i915: Add a delay in Displayport AUX transactions for compliance testing") removes this delay mentioning the hardware already meets this requirement, but as per the spec the delay mentioned in the spec specifies how long to wait for the receiver response before timeout. So the delay here to wait for timeout and not a delay after timeout. The DP spec specifies a delay after timeout and hence adding this delay. v2: fixed checkpatch warning and error v3: used proper indentation Signed-off-by: Arun R Murthy Acked-by: Jani Nikula --- drivers/gpu/drm/i915/display/intel_dp_aux.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c index 2bc119374555..722c9f210690 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c @@ -286,13 +286,9 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp, /* * DP CTS 1.2 Core Rev 1.1, 4.2.1.1 & 4.2.1.2 * 400us delay required for errors and timeouts - * Timeout errors from the HW already meet this - * requirement so skip to next iteration */ - if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR) - continue; - - if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) { + if (status & (DP_AUX_CH_CTL_RECEIVE_ERROR | + DP_AUX_CH_CTL_TIME_OUT_ERROR)) { usleep_range(400, 500); continue; }