[PATCH v4 2/2] drm/i915: Allow "max bpc" property to limit pipe_bpp

[Radhakrishna Sripada]

Use the newly added "max bpc" connector property to limit pipe bpp.

V3: Use drm_connector_state to access the "max bpc" property
V4: Initialize the drm property, add suuport to DP(Ville)

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Kishore Kadiyala <kishore.kadiyala at intel.com>
Cc: Manasi Navare <manasi.d.navare at intel.com>
Cc: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 25 +++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_dp.c      |  1 +
 drivers/gpu/drm/i915/intel_drv.h     |  2 ++
 drivers/gpu/drm/i915/intel_hdmi.c    |  7 +++++++
 drivers/gpu/drm/i915/intel_modes.c   | 21 +++++++++++++++++++++
 5 files changed, 56 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 4bb46f289c0d..216fd4b689b5 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -10783,6 +10783,28 @@ connected_sink_compute_bpp(struct intel_connector *connector,
 	}
 }
 
+static void
+connected_sink_max_bpp(struct drm_connector_state *conn_state,
+			     struct intel_crtc_state *pipe_config)
+{
+	switch (conn_state->max_bpc) {
+	case 8:
+	case 9:
+		pipe_config->pipe_bpp = 8*3;
+		break;
+	case 10:
+	case 11:
+		pipe_config->pipe_bpp = 10*3;
+		break;
+	case 12:
+		pipe_config->pipe_bpp = 12*3;
+		break;
+	default:
+		break;
+	}
+	DRM_DEBUG_KMS("Limiting display bpp to %d\n", pipe_config->pipe_bpp);
+}
+
 static int
 compute_baseline_pipe_bpp(struct intel_crtc *crtc,
 			  struct intel_crtc_state *pipe_config)
@@ -10811,6 +10833,9 @@ compute_baseline_pipe_bpp(struct intel_crtc *crtc,
 		if (connector_state->crtc != &crtc->base)
 			continue;
 
+		if (connector_state->max_bpc)
+			connected_sink_max_bpp(connector_state, pipe_config);
+
 		connected_sink_compute_bpp(to_intel_connector(connector),
 					   pipe_config);
 	}
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 436c22de33b6..1c2d38b7f6ab 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5719,6 +5719,7 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
 		intel_attach_force_audio_property(connector);
 
 	intel_attach_broadcast_rgb_property(connector);
+	intel_attach_max_bpc_property(connector, 6, 16);
 
 	if (intel_dp_is_edp(intel_dp)) {
 		u32 allowed_scalers;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index f5731215210a..b3c703dacc92 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1869,6 +1869,8 @@ int intel_ddc_get_modes(struct drm_connector *c, struct i2c_adapter *adapter);
 void intel_attach_force_audio_property(struct drm_connector *connector);
 void intel_attach_broadcast_rgb_property(struct drm_connector *connector);
 void intel_attach_aspect_ratio_property(struct drm_connector *connector);
+void intel_attach_max_bpc_property(struct drm_connector *connector, int min, int
+				   max);
 
 
 /* intel_overlay.c */
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index a2dab0b6bde6..e649bbf07642 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -2109,11 +2109,18 @@ static const struct drm_encoder_funcs intel_hdmi_enc_funcs = {
 static void
 intel_hdmi_add_properties(struct intel_hdmi *intel_hdmi, struct drm_connector *connector)
 {
+	struct drm_i915_private *dev_priv = to_i915(connector->dev);
+
 	intel_attach_force_audio_property(connector);
 	intel_attach_broadcast_rgb_property(connector);
 	intel_attach_aspect_ratio_property(connector);
 	drm_connector_attach_content_type_property(connector);
 	connector->state->picture_aspect_ratio = HDMI_PICTURE_ASPECT_NONE;
+
+	if (HAS_GMCH_DISPLAY(dev_priv))
+		intel_attach_max_bpc_property(connector, 8, 8);
+	else
+		intel_attach_max_bpc_property(connector, 8, 12);
 }
 
 /*
diff --git a/drivers/gpu/drm/i915/intel_modes.c b/drivers/gpu/drm/i915/intel_modes.c
index ca44bf368e24..eb1eaad0115e 100644
--- a/drivers/gpu/drm/i915/intel_modes.c
+++ b/drivers/gpu/drm/i915/intel_modes.c
@@ -133,3 +133,24 @@ intel_attach_aspect_ratio_property(struct drm_connector *connector)
 			connector->dev->mode_config.aspect_ratio_property,
 			DRM_MODE_PICTURE_ASPECT_NONE);
 }
+
+void
+intel_attach_max_bpc_property(struct drm_connector *connector, int min, int
+			       max)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_mode_config *config = &dev->mode_config;
+	struct drm_property *prop;
+
+	prop = config->max_bpc_property;
+	if (prop == NULL) {
+		prop = drm_property_create_range(dev, 0, "max bpc", min, max);
+		if (prop == NULL)
+			return;
+
+		config->max_bpc_property = prop;
+	}
+
+	drm_object_attach_property(&connector->base, prop, max);
+	connector->state->max_bpc = max;
+}
-- 
2.9.3