From patchwork Thu Nov 16 13:18:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Imre Deak X-Patchwork-Id: 13457888 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 80036C54FB9 for ; Thu, 16 Nov 2023 13:18:56 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C150810E5E3; Thu, 16 Nov 2023 13:18:51 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id DC09610E5D8; Thu, 16 Nov 2023 13:18:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1700140726; x=1731676726; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=SVdzxX+o76uHs97K1GMJS2pvOT9GVhRRg9CCqdfPUNQ=; b=ZfQAe/MQsN/SogaEsqA3apbNNEtTuJStfkVxlVOeCr7aWjrnRRvjkA+j yd8uWTGD4p04NvkSOBZQJQPGEHrZnUo62OGAFby5eUosXrTQnFt12jaSv XtIXcLlNOcPAhlpBI1Lxe8oG++2rWcarcsPfURsN7dJCxJE43YKU2CfRm WUFNkhAMflIQmd2Ak5r2+wexR9QsfeGT41qDIYQfVIdpSE0DjBaySQ/w/ iTKTwuJou36g8mlTAh+0M4dJF29nA1ZwUHHkRxOhT3g5Quap0kBMxj88e V/mrfOB6o/T8Zb0mAiO+CfVgtVdYDrdpDf0AJN/IsjAKzmnI5X+Pfo1bS w==; X-IronPort-AV: E=McAfee;i="6600,9927,10895"; a="422177151" X-IronPort-AV: E=Sophos;i="6.04,308,1695711600"; d="scan'208";a="422177151" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Nov 2023 05:18:46 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10895"; a="938834333" X-IronPort-AV: E=Sophos;i="6.04,308,1695711600"; d="scan'208";a="938834333" Received: from ideak-desk.fi.intel.com ([10.237.72.78]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Nov 2023 05:18:45 -0800 From: Imre Deak To: intel-gfx@lists.freedesktop.org Subject: [PATCH v2 02/11] drm/dp_mst: Fix PBN divider calculation for UHBR rates Date: Thu, 16 Nov 2023 15:18:32 +0200 Message-Id: <20231116131841.1588781-3-imre.deak@intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231116131841.1588781-1-imre.deak@intel.com> References: <20231116131841.1588781-1-imre.deak@intel.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" The current way of calculating the pbn_div value, the link BW per each MTP slot, worked only for DP 1.4 link rates. Fix things up for UHBR rates calculating with the correct channel coding efficiency based on the link rate. v2: - Return the fractional pbn_div value from drm_dp_get_vc_payload_bw(). Cc: Lyude Paul Cc: dri-devel@lists.freedesktop.org Signed-off-by: Imre Deak --- drivers/gpu/drm/display/drm_dp_mst_topology.c | 13 ++++++++++--- include/drm/display/drm_dp_helper.h | 13 +++++++++++++ 2 files changed, 23 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index 000d05e80352a..3fbd5585d5e6c 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -3585,14 +3585,18 @@ static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr, fixed20_12 drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr, int link_rate, int link_lane_count) { + int ch_coding_efficiency = + drm_dp_bw_channel_coding_efficiency(drm_dp_is_uhbr_rate(link_rate)); fixed20_12 ret; if (link_rate == 0 || link_lane_count == 0) drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n", link_rate, link_lane_count); - /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */ - ret.full = dfixed_const(link_rate * link_lane_count / 54000); + /* See DP v2.0 2.6.4.2, 2.7.6.3 VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */ + ret.full = DIV_ROUND_DOWN_ULL(mul_u32_u32(link_rate * link_lane_count, + ch_coding_efficiency), + (1000000ULL * 8 * 5400) >> 12); return ret; } @@ -4315,6 +4319,7 @@ int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state, struct drm_dp_mst_atomic_payload *payload = NULL; struct drm_connector_state *conn_state; int prev_slots = 0, prev_bw = 0, req_slots; + fixed20_12 req_slots_fp; topology_state = drm_atomic_get_mst_topology_state(state, mgr); if (IS_ERR(topology_state)) @@ -4342,7 +4347,9 @@ int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state, } } - req_slots = DIV_ROUND_UP(pbn, dfixed_trunc(topology_state->pbn_div)); + req_slots_fp.full = dfixed_div((fixed20_12)dfixed_init(pbn), topology_state->pbn_div); + req_slots_fp.full = dfixed_ceil(req_slots_fp); + req_slots = dfixed_trunc(req_slots_fp); drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n", port->connector->base.id, port->connector->name, diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h index c5f1079acb3b1..863b2e7add29e 100644 --- a/include/drm/display/drm_dp_helper.h +++ b/include/drm/display/drm_dp_helper.h @@ -252,6 +252,19 @@ drm_edp_backlight_supported(const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE]) return !!(edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP); } +/** + * drm_dp_is_uhbr_rate - Determine if a link rate is UHBR + * @link_rate: link rate in 10kbits/s units + * + * Determine if the provided link rate is an UHBR rate. + * + * Returns: %True if @link_rate is an UHBR rate. + */ +static inline bool drm_dp_is_uhbr_rate(int link_rate) +{ + return link_rate >= 1000000; +} + /* * DisplayPort AUX channel */