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>

7 files changed, 82 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 6b86e83ae128..3d4fd0181f65 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -707,6 +707,8 @@ typedef struct drm_i915_private {
 
         /* list of fbdev register on this device */
         struct intel_fbdev *fbdev;
+
+        struct drm_property *broadcast_rgb_property;
 } drm_i915_private_t;
 
 struct drm_i915_gem_object {
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 139d15234ffb..63ed072e5fe3 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1387,6 +1387,7 @@
 #define   SDVO_ENCODING_HDMI            (0x2 << 10)
 /** Requird for HDMI operation */
 #define   SDVO_NULL_PACKETS_DURING_VSYNC (1 << 9)
+#define   SDVO_COLOR_RANGE_16_235       (1 << 8)
 #define   SDVO_BORDER_ENABLE            (1 << 7)
 #define   SDVO_AUDIO_ENABLE             (1 << 6)
 /** New with 965, default is to be set */
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 7ffb324b6a7d..3216adcf54d2 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -49,6 +49,7 @@ struct intel_dp {
         uint8_t  link_configuration[DP_LINK_CONFIGURATION_SIZE];
         bool has_audio;
         int force_audio;
+        uint32_t color_range;
         int dpms_mode;
         uint8_t link_bw;
         uint8_t lane_count;
@@ -741,8 +742,8 @@ intel_dp_mode_set(struct drm_encoder *encoder, struct drm_display_mode *mode,
         struct drm_crtc *crtc = intel_dp->base.base.crtc;
         struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 
-        intel_dp->DP = (DP_VOLTAGE_0_4 |
-                       DP_PRE_EMPHASIS_0);
+        intel_dp->DP = DP_VOLTAGE_0_4 | DP_PRE_EMPHASIS_0;
+        intel_dp->DP |= intel_dp->color_range;
 
         if (adjusted_mode->flags & DRM_MODE_FLAG_PHSYNC)
                 intel_dp->DP |= DP_SYNC_HS_HIGH;
@@ -1680,6 +1681,7 @@ intel_dp_set_property(struct drm_connector *connector,
                       struct drm_property *property,
                       uint64_t val)
 {
+        struct drm_i915_private *dev_priv = connector->dev->dev_private;
         struct intel_dp *intel_dp = intel_attached_dp(connector);
         int ret;
 
@@ -1708,6 +1710,14 @@ intel_dp_set_property(struct drm_connector *connector,
                 goto done;
         }
 
+        if (property == dev_priv->broadcast_rgb_property) {
+                if (val == !!intel_dp->color_range)
+                        return 0;
+
+                intel_dp->color_range = val ? DP_COLOR_RANGE_16_235 : 0;
+                goto done;
+        }
+
         return -EINVAL;
 
 done:
@@ -1827,6 +1837,8 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
                 intel_dp->force_audio_property->values[1] = 1;
                 drm_connector_attach_property(connector, intel_dp->force_audio_property, 0);
         }
+
+        intel_attach_broadcast_rgb_property(connector);
 }
 
 void
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 08cd27d2c132..5daa991cb287 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -237,6 +237,8 @@ struct intel_unpin_work {
 int intel_ddc_get_modes(struct drm_connector *c, struct i2c_adapter *adapter);
 extern bool intel_ddc_probe(struct intel_encoder *intel_encoder, int ddc_bus);
 
+extern void intel_attach_broadcast_rgb_property(struct drm_connector *connector);
+
 extern void intel_crt_init(struct drm_device *dev);
 extern void intel_hdmi_init(struct drm_device *dev, int sdvox_reg);
 void intel_dip_infoframe_csum(struct dip_infoframe *avi_if);
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)
diff --git a/drivers/gpu/drm/i915/intel_modes.c b/drivers/gpu/drm/i915/intel_modes.c
index f70b7cf32bff..9034dd8f33c7 100644
--- a/drivers/gpu/drm/i915/intel_modes.c
+++ b/drivers/gpu/drm/i915/intel_modes.c
@@ -80,3 +80,33 @@ int intel_ddc_get_modes(struct drm_connector *connector,
 
         return ret;
 }
+
+static const char *broadcast_rgb_names[] = {
+        "Full",
+        "Limited 16:235",
+};
+
+void
+intel_attach_broadcast_rgb_property(struct drm_connector *connector)
+{
+        struct drm_device *dev = connector->dev;
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        struct drm_property *prop;
+        int i;
+
+        prop = dev_priv->broadcast_rgb_property;
+        if (prop == NULL) {
+                prop = drm_property_create(dev, DRM_MODE_PROP_ENUM,
+                                           "Broadcast RGB",
+                                           ARRAY_SIZE(broadcast_rgb_names));
+                if (prop == NULL)
+                        return;
+
+                for (i = 0; i < ARRAY_SIZE(broadcast_rgb_names); i++)
+                        drm_property_add_enum(prop, i, i, broadcast_rgb_names[i]);
+
+                dev_priv->broadcast_rgb_property = prop;
+        }
+
+        drm_connector_attach_property(connector, prop, 0);
+}
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 19c817a2df0c..9698e91f6a37 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -93,6 +93,12 @@ struct intel_sdvo {
         uint16_t attached_output;
 
         /**
+         * This is used to select the color range of RBG outputs in HDMI mode.
+         * It is only valid when using TMDS encoding and 8 bit per color mode.
+         */
+        uint32_t color_range;
+
+        /**
          * This is set if we're going to treat the device as TV-out.
          *
          * While we have these nice friendly flags for output types that ought
@@ -1056,6 +1062,8 @@ static void intel_sdvo_mode_set(struct drm_encoder *encoder,
         /* Set the SDVO control regs. */
         if (INTEL_INFO(dev)->gen >= 4) {
                 sdvox = 0;
+                if (intel_sdvo->is_hdmi)
+                        sdvox |= intel_sdvo->color_range;
                 if (INTEL_INFO(dev)->gen < 5)
                         sdvox |= SDVO_BORDER_ENABLE;
                 if (adjusted_mode->flags & DRM_MODE_FLAG_PVSYNC)
@@ -1695,6 +1703,7 @@ intel_sdvo_set_property(struct drm_connector *connector,
 {
         struct intel_sdvo *intel_sdvo = intel_attached_sdvo(connector);
         struct intel_sdvo_connector *intel_sdvo_connector = to_intel_sdvo_connector(connector);
+        struct drm_i915_private *dev_priv = connector->dev->dev_private;
         uint16_t temp_value;
         uint8_t cmd;
         int ret;
@@ -1724,6 +1733,14 @@ intel_sdvo_set_property(struct drm_connector *connector,
                 goto done;
         }
 
+        if (property == dev_priv->broadcast_rgb_property) {
+                if (val == !!intel_sdvo->color_range)
+                        return 0;
+
+                intel_sdvo->color_range = val ? SDVO_COLOR_RANGE_16_235 : 0;
+                goto done;
+        }
+
 #define CHECK_PROPERTY(name, NAME) \
         if (intel_sdvo_connector->name == property) { \
                 if (intel_sdvo_connector->cur_##name == temp_value) return 0; \
@@ -2028,6 +2045,9 @@ intel_sdvo_add_hdmi_properties(struct intel_sdvo_connector *connector)
                 drm_connector_attach_property(&connector->base.base,
                                               connector->force_audio_property, 0);
         }
+
+        if (INTEL_INFO(dev)->gen >= 4 && IS_MOBILE(dev))
+                intel_attach_broadcast_rgb_property(&connector->base.base);
 }
 
 static bool