[PATCH v2 4/4] drm/i915: Provide the quantization range in the AVI infoframe

[ville.syrjala at linux.intel.com]

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

The AVI infoframe is able to inform the display whether the source is
sending full or limited range RGB data.

As per CEA-861 [1] we must first check whether the display reports the
quantization range as selectable, and if so we can set the approriate
bits in the AVI inforframe.

[1] CEA-861-E - 6.4 Format of Version 2 AVI InfoFrame

v2: Give the Q bits better names, add spec chapter information

Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_drv.h  |    4 ++++
 drivers/gpu/drm/i915/intel_hdmi.c |   11 +++++++++++
 drivers/gpu/drm/i915/intel_sdvo.c |   16 ++++++++++++++--
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 1a698c6..aeff0d1 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -289,6 +289,9 @@ struct cxsr_latency {
 #define DIP_LEN_AVI     13
 #define DIP_AVI_PR_1    0
 #define DIP_AVI_PR_2    1
+#define DIP_AVI_RGB_QUANT_RANGE_DEFAULT	(0 << 2)
+#define DIP_AVI_RGB_QUANT_RANGE_LIMITED	(1 << 2)
+#define DIP_AVI_RGB_QUANT_RANGE_FULL	(2 << 2)
 
 #define DIP_TYPE_SPD	0x83
 #define DIP_VERSION_SPD	0x1
@@ -347,6 +350,7 @@ struct intel_hdmi {
 	bool has_hdmi_sink;
 	bool has_audio;
 	enum hdmi_force_audio force_audio;
+	bool rgb_quant_range_selectable;
 	void (*write_infoframe)(struct drm_encoder *encoder,
 				struct dip_infoframe *frame);
 	void (*set_infoframes)(struct drm_encoder *encoder,
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index db67be6..d53b731 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -331,6 +331,7 @@ static void intel_set_infoframe(struct drm_encoder *encoder,
 static void intel_hdmi_set_avi_infoframe(struct drm_encoder *encoder,
 					 struct drm_display_mode *adjusted_mode)
 {
+	struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(encoder);
 	struct dip_infoframe avi_if = {
 		.type = DIP_TYPE_AVI,
 		.ver = DIP_VERSION_AVI,
@@ -340,6 +341,13 @@ static void intel_hdmi_set_avi_infoframe(struct drm_encoder *encoder,
 	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLCLK)
 		avi_if.body.avi.YQ_CN_PR |= DIP_AVI_PR_2;
 
+	if (intel_hdmi->rgb_quant_range_selectable) {
+		if (adjusted_mode->private_flags & INTEL_MODE_LIMITED_COLOR_RANGE)
+			avi_if.body.avi.ITC_EC_Q_SC |= DIP_AVI_RGB_QUANT_RANGE_LIMITED;
+		else
+			avi_if.body.avi.ITC_EC_Q_SC |= DIP_AVI_RGB_QUANT_RANGE_FULL;
+	}
+
 	avi_if.body.avi.VIC = drm_mode_cea_vic(adjusted_mode);
 
 	intel_set_infoframe(encoder, &avi_if);
@@ -825,6 +833,7 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
 
 	intel_hdmi->has_hdmi_sink = false;
 	intel_hdmi->has_audio = false;
+	intel_hdmi->rgb_quant_range_selectable = false;
 	edid = drm_get_edid(connector,
 			    intel_gmbus_get_adapter(dev_priv,
 						    intel_hdmi->ddc_bus));
@@ -836,6 +845,8 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
 				intel_hdmi->has_hdmi_sink =
 						drm_detect_hdmi_monitor(edid);
 			intel_hdmi->has_audio = drm_detect_monitor_audio(edid);
+			intel_hdmi->rgb_quant_range_selectable =
+				drm_rgb_quant_range_selectable(edid);
 		}
 		kfree(edid);
 	}
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 3e34a35..f01063a 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -126,6 +126,7 @@ struct intel_sdvo {
 	bool is_hdmi;
 	bool has_hdmi_monitor;
 	bool has_hdmi_audio;
+	bool rgb_quant_range_selectable;
 
 	/**
 	 * This is set if we detect output of sdvo device as LVDS and
@@ -947,7 +948,8 @@ static bool intel_sdvo_write_infoframe(struct intel_sdvo *intel_sdvo,
 				    &tx_rate, 1);
 }
 
-static bool intel_sdvo_set_avi_infoframe(struct intel_sdvo *intel_sdvo)
+static bool intel_sdvo_set_avi_infoframe(struct intel_sdvo *intel_sdvo,
+					 const struct drm_display_mode *adjusted_mode)
 {
 	struct dip_infoframe avi_if = {
 		.type = DIP_TYPE_AVI,
@@ -956,6 +958,13 @@ static bool intel_sdvo_set_avi_infoframe(struct intel_sdvo *intel_sdvo)
 	};
 	uint8_t sdvo_data[4 + sizeof(avi_if.body.avi)];
 
+	if (intel_sdvo->rgb_quant_range_selectable) {
+		if (adjusted_mode->private_flags & INTEL_MODE_LIMITED_COLOR_RANGE)
+			avi_if.body.avi.ITC_EC_Q_SC |= DIP_AVI_RGB_QUANT_RANGE_LIMITED;
+		else
+			avi_if.body.avi.ITC_EC_Q_SC |= DIP_AVI_RGB_QUANT_RANGE_FULL;
+	}
+
 	intel_dip_infoframe_csum(&avi_if);
 
 	/* sdvo spec says that the ecc is handled by the hw, and it looks like
@@ -1134,7 +1143,7 @@ static void intel_sdvo_mode_set(struct drm_encoder *encoder,
 		intel_sdvo_set_encode(intel_sdvo, SDVO_ENCODE_HDMI);
 		intel_sdvo_set_colorimetry(intel_sdvo,
 					   SDVO_COLORIMETRY_RGB256);
-		intel_sdvo_set_avi_infoframe(intel_sdvo);
+		intel_sdvo_set_avi_infoframe(intel_sdvo, adjusted_mode);
 	} else
 		intel_sdvo_set_encode(intel_sdvo, SDVO_ENCODE_DVI);
 
@@ -1526,6 +1535,8 @@ intel_sdvo_tmds_sink_detect(struct drm_connector *connector)
 			if (intel_sdvo->is_hdmi) {
 				intel_sdvo->has_hdmi_monitor = drm_detect_hdmi_monitor(edid);
 				intel_sdvo->has_hdmi_audio = drm_detect_monitor_audio(edid);
+				intel_sdvo->rgb_quant_range_selectable =
+					drm_rgb_quant_range_selectable(edid);
 			}
 		} else
 			status = connector_status_disconnected;
@@ -1577,6 +1588,7 @@ intel_sdvo_detect(struct drm_connector *connector, bool force)
 
 	intel_sdvo->has_hdmi_monitor = false;
 	intel_sdvo->has_hdmi_audio = false;
+	intel_sdvo->rgb_quant_range_selectable = false;
 
 	if ((intel_sdvo_connector->output_flag & response) == 0)
 		ret = connector_status_disconnected;
-- 
1.7.8.6