From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932219AbcHSHMU (ORCPT ); Fri, 19 Aug 2016 03:12:20 -0400 Received: from mx2.suse.de ([195.135.220.15]:50017 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755580AbcHSHMM (ORCPT ); Fri, 19 Aug 2016 03:12:12 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Mario Kleiner , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Daniel Vetter , Dave Airlie , Jiri Slaby Subject: [PATCH 3.12 087/100] drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown" Date: Fri, 19 Aug 2016 09:11:26 +0200 Message-Id: <55ddae2b80f8517f074a403615a434e22cb67d09.1471589700.git.jslaby@suse.cz> X-Mailer: git-send-email 2.9.3 In-Reply-To: References: In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mario Kleiner 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 196f954e250943df414efd3d632254c29be38e59 upstream. This reverts commit 013dd9e03872 ("drm/i915/dp: fall back to 18 bpp when sink capability is unknown") This commit introduced a regression into stable kernels, as it reduces output color depth to 6 bpc for any video sink connected to a Displayport connector if that sink doesn't report a specific color depth via EDID, or if our EDID parser doesn't actually recognize the proper bpc from EDID. Affected are active DisplayPort->VGA converters and active DisplayPort->DVI converters. Both should be able to handle 8 bpc, but are degraded to 6 bpc with this patch. The reverted commit was meant to fix Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=105331 A followup patch implements a fix for that specific bug, which is caused by a faulty EDID of the affected DP panel by adding a new EDID quirk for that panel. DP 18 bpp fallback handling and other improvements to DP sink bpc detection will be handled for future kernels in a separate series of patches. Please backport to stable. Signed-off-by: Mario Kleiner Acked-by: Jani Nikula Cc: Ville Syrjälä Cc: Daniel Vetter Signed-off-by: Dave Airlie Signed-off-by: Jiri Slaby --- drivers/gpu/drm/i915/intel_display.c | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 05f8b51cd42a..57d5abc420d1 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -8220,21 +8220,11 @@ connected_sink_compute_bpp(struct intel_connector * connector, pipe_config->pipe_bpp = connector->base.display_info.bpc*3; } - /* Clamp bpp to default limit on screens without EDID 1.4 */ - if (connector->base.display_info.bpc == 0) { - int type = connector->base.connector_type; - int clamp_bpp = 24; - - /* Fall back to 18 bpp when DP sink capability is unknown. */ - if (type == DRM_MODE_CONNECTOR_DisplayPort || - type == DRM_MODE_CONNECTOR_eDP) - clamp_bpp = 18; - - if (bpp > clamp_bpp) { - DRM_DEBUG_KMS("clamping display bpp (was %d) to default limit of %d\n", - bpp, clamp_bpp); - pipe_config->pipe_bpp = clamp_bpp; - } + /* Clamp bpp to 8 on screens without EDID 1.4 */ + if (connector->base.display_info.bpc == 0 && bpp > 24) { + DRM_DEBUG_KMS("clamping display bpp (was %d) to default limit of 24\n", + bpp); + pipe_config->pipe_bpp = 24; } } -- 2.9.3