[Intel-gfx] [PATCH 5/5] 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>
Reviewed-by: Jani Nikula <jani.nikula at 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 7523558190d1..61ee22664ee7 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4821,6 +4821,11 @@ 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 d94193aa6ffc..a3cb89ee7fd0 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -1205,6 +1205,11 @@ 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;
-- 
2.7.4