[PATCH 2/2] drm/i915: do not default to 18 bpp for eDP if missing from VBT

[Jani Nikula <jani.nikula@intel.com>]

Do not clamp eDP to 18 bpp by default if the eDP BDB is missing from VBT.

This is hopefully a better version of

commit 4344b813f105a19f793f1fd93ad775b784648b95
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Aug 10 11:10:20 2012 +0200

    drm/i915: ignore eDP bpc settings from vbt

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/intel_bios.c    |   11 ++---------
 drivers/gpu/drm/i915/intel_display.c |    2 +-
 2 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 0ed6baf..56846ed 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -499,12 +499,8 @@ parse_edp(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
 
 	edp = find_section(bdb, BDB_EDP);
 	if (!edp) {
-		if (SUPPORTS_EDP(dev_priv->dev) && dev_priv->edp.support) {
-			DRM_DEBUG_KMS("No eDP BDB found but eDP panel "
-				      "supported, assume %dbpp panel color "
-				      "depth.\n",
-				      dev_priv->edp.bpp);
-		}
+		if (SUPPORTS_EDP(dev_priv->dev) && dev_priv->edp.support)
+			DRM_DEBUG_KMS("No eDP BDB found but eDP panel supported.\n");
 		return;
 	}
 
@@ -657,9 +653,6 @@ init_vbt_defaults(struct drm_i915_private *dev_priv)
 	dev_priv->lvds_use_ssc = 1;
 	dev_priv->lvds_ssc_freq = intel_bios_ssc_frequency(dev, 1);
 	DRM_DEBUG_KMS("Set default to SSC at %dMHz\n", dev_priv->lvds_ssc_freq);
-
-	/* eDP data */
-	dev_priv->edp.bpp = 18;
 }
 
 static int __init intel_no_opregion_vbt_callback(const struct dmi_system_id *id)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0997e60..b11e8c1 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4155,7 +4155,7 @@ static bool intel_choose_pipe_bpp_dither(struct drm_crtc *crtc,
 			/* Use VBT settings if we have an eDP panel */
 			unsigned int edp_bpc = dev_priv->edp.bpp / 3;
 
-			if (edp_bpc < display_bpc) {
+			if (edp_bpc && edp_bpc < display_bpc) {
 				DRM_DEBUG_KMS("clamping display bpc (was %d) to eDP (%d)\n", display_bpc, edp_bpc);
 				display_bpc = edp_bpc;
 			}
-- 
1.7.9.5