From patchwork Tue Oct 21 10:52:49 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dheeraj Jamwal X-Patchwork-Id: 5118781 Return-Path: X-Original-To: patchwork-ltsi-dev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 35EB7C11AC for ; Tue, 21 Oct 2014 11:44:02 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6DC08200E8 for ; Tue, 21 Oct 2014 11:44:01 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9221920121 for ; Tue, 21 Oct 2014 11:44:00 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 86E7E107D; Tue, 21 Oct 2014 11:08:08 +0000 (UTC) X-Original-To: ltsi-dev@lists.linuxfoundation.org Delivered-To: ltsi-dev@mail.linuxfoundation.org Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 8D77C107D for ; Tue, 21 Oct 2014 11:08:06 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 365FA201F0 for ; Tue, 21 Oct 2014 11:08:06 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 21 Oct 2014 04:08:05 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,761,1406617200"; d="scan'208";a="617797296" Received: from ubuntu-desktop.png.intel.com ([10.221.122.25]) by fmsmga002.fm.intel.com with ESMTP; 21 Oct 2014 04:08:04 -0700 From: Dheeraj Jamwal To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 21 Oct 2014 18:52:49 +0800 Message-Id: <1413889294-31328-570-git-send-email-dheerajx.s.jamwal@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> References: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org Subject: [LTSI-dev] [PATCH 0569/1094] drm/i915/dp: force eDP lane count to max available lanes on BDW X-BeenThere: ltsi-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: "A list to discuss patches, development, and other things related to the LTSI project" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org X-Virus-Scanned: ClamAV using ClamSMTP From: Jani Nikula There are certain BDW high res eDP machines that regressed due to commit 38aecea0ccbb909d635619cba22f1891e589b434 Author: Daniel Vetter Date: Mon Mar 3 11:18:10 2014 +0100 drm/i915: reverse dp link param selection, prefer fast over wide again The commit lead to 2 lanes at 5.4 Gbps being used instead of 4 lanes at 2.7 Gbps on the affected machines. Link training succeeded for both, but the screen remained blank with the former config. Further investigation showed that 4 lanes at 5.4 Gbps worked also. The root cause for the blank screen using 2 lanes remains unknown, but apparently the driver for a certain other operating system by default uses the max available lanes. Follow suit on Broadwell eDP, for at least until we figure out what is going on. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76711 Reviewed-by: Daniel Vetter Reviewed-by: Rodrigo Vivi Tested-by: Rodrigo Vivi Signed-off-by: Jani Nikula (cherry picked from commit f4cdbc21444a45d207a8dc175f44d2facfbd0845) Signed-off-by: Dheeraj Jamwal --- drivers/gpu/drm/i915/intel_dp.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 8233f2a..2a00cb8 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -810,7 +810,12 @@ intel_dp_compute_config(struct intel_encoder *encoder, bpp = dev_priv->vbt.edp_bpp; } - if (dev_priv->vbt.edp_lanes) { + if (IS_BROADWELL(dev)) { + /* Yes, it's an ugly hack. */ + min_lane_count = max_lane_count; + DRM_DEBUG_KMS("forcing lane count to max (%u) on BDW\n", + min_lane_count); + } else if (dev_priv->vbt.edp_lanes) { min_lane_count = min(dev_priv->vbt.edp_lanes, max_lane_count); DRM_DEBUG_KMS("using min %u lanes per VBT\n",