[Intel-gfx] [PATCH 16/16] drm/i915: Reject 'Center' scaling mode for eDP/DSI on GMCH platforms

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

We don't have a LVDS_BORDER_ENABLE type of bit for either eDP or DSI,
and just trying to frob the display timings to include borders results
in a corrupted picture. So reject the 'Center' scaling mode on GMCH
platforms for eDP and DSI.

TODO: Should really filter out the unsupported modes from the prop,
but that would be fairly invasive since the prop is now created and
stored by drm core. So leave it for a rainy day.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c  | 5 +++++
 drivers/gpu/drm/i915/intel_dsi.c | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 0e326e776e8f..f268bda6d55e 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4754,6 +4754,11 @@ intel_dp_set_property(struct drm_connector *connector,
 			DRM_DEBUG_KMS("no scaling not supported\n");
 			return -EINVAL;
 		}
+		if (HAS_GMCH_DISPLAY(dev_priv) &&
+		    val == DRM_MODE_SCALE_CENTER) {
+			DRM_DEBUG_KMS("centering not supported\n");
+			return -EINVAL;
+		}
 
 		if (intel_connector->panel.fitting_mode == val) {
 			/* the eDP scaling property is not changed */
diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 3823425a3e36..0ffa125a83e7 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -1082,6 +1082,11 @@ static int intel_dsi_set_property(struct drm_connector *connector,
 			DRM_DEBUG_KMS("no scaling not supported\n");
 			return -EINVAL;
 		}
+		if (HAS_GMCH_DISPLAY(dev) &&
+		    val == DRM_MODE_SCALE_CENTER) {
+			DRM_DEBUG_KMS("centering not supported\n");
+			return -EINVAL;
+		}
 
 		if (intel_connector->panel.fitting_mode == val)
 			return 0;
-- 
2.4.10