drm/i915: ignore eDP bpc settings from vbt

commit 4344b813f105a19f793f1fd93ad775b784648b95 upstream.

This has originally been introduced to not oversubscribe the dp links
in

commit 885a5fb5b120a5c7e0b3baad7b0feb5a89f76c18
Author: Zhenyu Wang <zhenyuw@linux.intel.com>
Date:   Tue Jan 12 05:38:31 2010 +0800

    drm/i915: fix pixel color depth setting on eDP

Since then we've fixed up the dp link bandwidth calculation code and
should now automatically fall back to 6bpc dithering. So this is
unnecessary.

Furthermore it seems to break the new MacbookPro with retina display,
hence let's just rip this out.

Reported-by: Benoit Gschwind <gschwind@gnu-log.net>
Cc: Benoit Gschwind <gschwind@gnu-log.net>
Cc: Francois Rigaut <frigaut@gmail.com>
Tested-by: Benoit Gschwind <gschwind@gnu-log.net>
Tested-by: Bernhard Froemel <froemel at vmars tuwien.ac.at>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--

Testing feedback highgly welcome, and thanks for Benoit for finding
out that the bpc computations are busted.
-Daniel

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d4d162f6babc436e154a85519fc201f4177318f1..3de3d9b670bb175cc6458e45dfd25fe5d2f66745 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4982,17 +4982,6 @@ static bool intel_choose_pipe_bpp_dither(struct drm_crtc *crtc,
                        continue;
                }
 
-               if (intel_encoder->type == INTEL_OUTPUT_EDP) {
-                       /* Use VBT settings if we have an eDP panel */
-                       unsigned int edp_bpc = dev_priv->edp.bpp / 3;
-
-                       if (edp_bpc < display_bpc) {
-                               DRM_DEBUG_KMS("clamping display bpc (was %d) to eDP (%d)\n", display_bpc, edp_bpc);
-                               display_bpc = edp_bpc;
-                       }
-                       continue;
-               }
-
                /* Not one of the known troublemakers, check the EDID */
                list_for_each_entry(connector, &dev->mode_config.connector_list,
                                    head) {