From patchwork Sat Nov 19 02:59:01 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Navare, Manasi" X-Patchwork-Id: 9437777 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7D96360237 for ; Sat, 19 Nov 2016 02:57:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6EA2929A43 for ; Sat, 19 Nov 2016 02:57:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3580629A46; Sat, 19 Nov 2016 02:57:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 1783429A43 for ; Sat, 19 Nov 2016 02:57:08 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7C5EE6E2B8; Sat, 19 Nov 2016 02:56:53 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9D7EA6E2A5; Sat, 19 Nov 2016 02:56:51 +0000 (UTC) Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga102.jf.intel.com with ESMTP; 18 Nov 2016 18:56:51 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,513,1473145200"; d="scan'208";a="33059373" Received: from manasi-otcmedia.jf.intel.com ([10.7.199.175]) by orsmga005.jf.intel.com with ESMTP; 18 Nov 2016 18:56:51 -0800 From: Manasi Navare To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: [PATCH 4/5] drm/i915: Find fallback link rate/lane count Date: Fri, 18 Nov 2016 18:59:01 -0800 Message-Id: <1479524342-22021-5-git-send-email-manasi.d.navare@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1479524342-22021-1-git-send-email-manasi.d.navare@intel.com> References: <1479524342-22021-1-git-send-email-manasi.d.navare@intel.com> Cc: Manasi Navare , Daniel Vetter X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP If link training fails, then we need to fallback to lower link rate first and if link training fails at RBR, then fallback to lower lane count. This function finds the next lower link rate/lane count value after link training failure. v5: * Start the fallback at the lane count value passed not the max lane count (Jani Nikula) v4: * Remove the redundant variable link_train_failed v3: * Remove fallback_link_rate_index variable, just obtain that using the helper intel_dp_link_rate_index (Jani Nikula) v2: Squash the patch that returns the link rate index (Jani Nikula) Acked-by: Tony Cheng Acked-by: Harry Wentland Cc: Ville Syrjala Cc: Jani Nikula Cc: Daniel Vetter Signed-off-by: Manasi Navare --- drivers/gpu/drm/i915/intel_dp.c | 40 ++++++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_drv.h | 4 ++++ 2 files changed, 44 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 90283ed..3a72014 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -288,6 +288,46 @@ static int intel_dp_common_rates(struct intel_dp *intel_dp, common_rates); } +static int intel_dp_link_rate_index(struct intel_dp *intel_dp, + int *common_rates, int link_rate) +{ + int common_len; + int index; + + common_len = intel_dp_common_rates(intel_dp, common_rates); + for (index = 0; index < common_len; index++) { + if (link_rate == common_rates[common_len - index - 1]) + return common_len - index - 1; + } + + return -1; +} + +int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp, + int link_rate, uint8_t lane_count) +{ + int common_rates[DP_MAX_SUPPORTED_RATES] = {}; + int common_len; + int link_rate_index = -1; + + common_len = intel_dp_common_rates(intel_dp, common_rates); + link_rate_index = intel_dp_link_rate_index(intel_dp, + common_rates, + link_rate); + if (link_rate_index > 0) { + intel_dp->fallback_link_rate = common_rates[link_rate_index - 1]; + intel_dp->fallback_lane_count = lane_count; + } else if (lane_count > 1) { + intel_dp->fallback_link_rate = common_rates[common_len - 1]; + intel_dp->fallback_lane_count = lane_count >> 1; + } else { + DRM_ERROR("Link Training Unsuccessful\n"); + return -1; + } + + return 0; +} + static enum drm_mode_status intel_dp_mode_valid(struct drm_connector *connector, struct drm_display_mode *mode) diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index cd132c2..e1c43a9 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -887,6 +887,8 @@ struct intel_dp { uint32_t DP; int link_rate; uint8_t lane_count; + int fallback_link_rate; + uint8_t fallback_lane_count; uint8_t sink_count; bool link_mst; bool has_audio; @@ -1383,6 +1385,8 @@ bool intel_dp_init_connector(struct intel_digital_port *intel_dig_port, void intel_dp_set_link_params(struct intel_dp *intel_dp, int link_rate, uint8_t lane_count, bool link_mst); +int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp, + int link_rate, uint8_t lane_count); void intel_dp_start_link_train(struct intel_dp *intel_dp); void intel_dp_stop_link_train(struct intel_dp *intel_dp); void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode);