From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754890AbbFQWvY (ORCPT ); Wed, 17 Jun 2015 18:51:24 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:35667 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751259AbbFQWaI (ORCPT ); Wed, 17 Jun 2015 18:30:08 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Lukas Wunner , Jani Nikula , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 047/122] drm/i915: Assume dual channel LVDS if pixel clock necessitates it Date: Wed, 17 Jun 2015 15:27:54 -0700 Message-Id: <1434580149-3095-48-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1434580149-3095-1-git-send-email-kamal@canonical.com> References: <1434580149-3095-1-git-send-email-kamal@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt22 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Lukas Wunner commit 6f317cfe42c9d8a7c9c1a327d2f1bcc517a3cd91 upstream. Single channel LVDS maxes out at 112 MHz, anything above must be dual channel. This avoids the need to specify i915.lvds_channel_mode=2 on all 17" MacBook Pro models with i915 graphics since they had 1920x1200 (193 MHz), plus those 15" pre-retina models which had a resolution of 1680x1050 (119 MHz) as a BTO option. Source for 112 MHz limit of single channel LVDS is section 2.3 of: https://01.org/linuxgraphics/sites/default/files/documentation/ivb_ihd_os_vol3_part4.pdf v2: Avoid hardcoding 17" models by assuming dual channel LVDS if the resolution necessitates it, suggested by Jani Nikula. v3: Fix typo, thanks Joonas Lahtinen. v4: Split commit in two, suggested by Ville Syrjälä. Signed-off-by: Lukas Wunner Tested-by: Lukas Wunner Reviewed-by: Ville Syrjälä [Jani: included spec reference into the commit message] Signed-off-by: Jani Nikula [ kamal: backport to 3.13-stable ] Signed-off-by: Kamal Mostafa --- drivers/gpu/drm/i915/intel_lvds.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c index a837510..0f3a188 100644 --- a/drivers/gpu/drm/i915/intel_lvds.c +++ b/drivers/gpu/drm/i915/intel_lvds.c @@ -891,6 +891,11 @@ static bool compute_is_dual_link_lvds(struct intel_lvds_encoder *lvds_encoder) if (i915_lvds_channel_mode > 0) return i915_lvds_channel_mode == 2; + /* single channel LVDS is limited to 112 MHz */ + if (lvds_encoder->attached_connector->base.panel.fixed_mode->clock + > 112999) + return true; + if (dmi_check_system(intel_dual_link_lvds)) return true; @@ -1131,6 +1136,8 @@ void intel_lvds_init(struct drm_device *dev) goto failed; out: + intel_panel_init(&intel_connector->panel, fixed_mode); + lvds_encoder->is_dual_link = compute_is_dual_link_lvds(lvds_encoder); DRM_DEBUG_KMS("detected %s-link lvds configuration\n", lvds_encoder->is_dual_link ? "dual" : "single"); @@ -1142,7 +1149,6 @@ out: } drm_sysfs_connector_add(connector); - intel_panel_init(&intel_connector->panel, fixed_mode); intel_panel_setup_backlight(connector); return; -- 1.9.1