drm/i915: Add support for limited color range of broadcast outputs

In order to prevent "crushed blacks" on TVs, the range of the RGB output
may be limited to 16-235. This used to be available through Xorg under
the "Broadcast RGB" option, so reintroduce support for KMS.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34543
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index c635c9e357b9..f289b8642976 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -41,6 +41,7 @@ struct intel_hdmi {
         struct intel_encoder base;
         u32 sdvox_reg;
         int ddc_bus;
+        uint32_t color_range;
         bool has_hdmi_sink;
         bool has_audio;
         int force_audio;
@@ -124,6 +125,7 @@ static void intel_hdmi_mode_set(struct drm_encoder *encoder,
         u32 sdvox;
 
         sdvox = SDVO_ENCODING_HDMI | SDVO_BORDER_ENABLE;
+        sdvox |= intel_hdmi->color_range;
         if (adjusted_mode->flags & DRM_MODE_FLAG_PVSYNC)
                 sdvox |= SDVO_VSYNC_ACTIVE_HIGH;
         if (adjusted_mode->flags & DRM_MODE_FLAG_PHSYNC)
@@ -278,6 +280,7 @@ intel_hdmi_set_property(struct drm_connector *connector,
                       uint64_t val)
 {
         struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
+        struct drm_i915_private *dev_priv = connector->dev->dev_private;
         int ret;
 
         ret = drm_connector_property_set_value(connector, property, val);
@@ -305,6 +308,14 @@ intel_hdmi_set_property(struct drm_connector *connector,
                 goto done;
         }
 
+        if (property == dev_priv->broadcast_rgb_property) {
+                if (val == !!intel_hdmi->color_range)
+                        return 0;
+
+                intel_hdmi->color_range = val ? SDVO_COLOR_RANGE_16_235 : 0;
+                goto done;
+        }
+
         return -EINVAL;
 
 done:
@@ -363,6 +374,8 @@ intel_hdmi_add_properties(struct intel_hdmi *intel_hdmi, struct drm_connector *c
                 intel_hdmi->force_audio_property->values[1] = 1;
                 drm_connector_attach_property(connector, intel_hdmi->force_audio_property, 0);
         }
+
+        intel_attach_broadcast_rgb_property(connector);
 }
 
 void intel_hdmi_init(struct drm_device *dev, int sdvox_reg)