From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:33660 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753977AbcHRMHi (ORCPT ); Thu, 18 Aug 2016 08:07:38 -0400 Subject: Patch "drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown"" has been added to the 3.14-stable tree To: mario.kleiner.de@gmail.com, airlied@redhat.com, daniel.vetter@ffwll.ch, gregkh@linuxfoundation.org, jani.nikula@intel.com, ville.syrjala@linux.intel.com Cc: , From: Date: Thu, 18 Aug 2016 14:07:46 +0200 Message-ID: <147152206616993@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown" to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-i915-dp-revert-drm-i915-dp-fall-back-to-18-bpp-when-sink-capability-is-unknown.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 196f954e250943df414efd3d632254c29be38e59 Mon Sep 17 00:00:00 2001 From: Mario Kleiner Date: Wed, 6 Jul 2016 12:05:45 +0200 Subject: drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown" MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Mario Kleiner 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: Greg Kroah-Hartman --- drivers/gpu/drm/i915/intel_display.c | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-) --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -8841,21 +8841,11 @@ connected_sink_compute_bpp(struct intel_ 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; } } Patches currently in stable-queue which might be from mario.kleiner.de@gmail.com are queue-3.14/drm-i915-dp-revert-drm-i915-dp-fall-back-to-18-bpp-when-sink-capability-is-unknown.patch