drm/radeon/kms: add support for load detection on dp bridges

dp to vga bridges for example.
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_connectors.c

@@ -1235,6 +1235,16 @@ radeon_dp_detect(struct drm_connector *connector, bool force)
 					ret = connector_status_connected;
 			}
 		}
+
+		if ((ret == connector_status_disconnected) &&
+		    radeon_connector->dac_load_detect) {
+			struct drm_encoder *encoder = radeon_best_single_encoder(connector);
+			struct drm_encoder_helper_funcs *encoder_funcs;
+			if (encoder) {
+				encoder_funcs = encoder->helper_private;
+				ret = encoder_funcs->detect(encoder, connector);
+			}
+		}
 	}
 
 	radeon_connector_update_scratch_regs(connector, ret);
@@ -1408,6 +1418,10 @@ radeon_add_atom_connector(struct drm_device *dev,
 		default:
 			connector->interlace_allowed = true;
 			connector->doublescan_allowed = true;
+			radeon_connector->dac_load_detect = true;
+			drm_connector_attach_property(&radeon_connector->base,
+						      rdev->mode_info.load_detect_property,
+						      1);
 			break;
 		case DRM_MODE_CONNECTOR_DVII:
 		case DRM_MODE_CONNECTOR_DVID:
@@ -1429,6 +1443,12 @@ radeon_add_atom_connector(struct drm_device *dev,
 				connector->doublescan_allowed = true;
 			else
 				connector->doublescan_allowed = false;
+			if (connector_type == DRM_MODE_CONNECTOR_DVII) {
+				radeon_connector->dac_load_detect = true;
+				drm_connector_attach_property(&radeon_connector->base,
+							      rdev->mode_info.load_detect_property,
+							      1);
+			}
 			break;
 		case DRM_MODE_CONNECTOR_LVDS:
 		case DRM_MODE_CONNECTOR_eDP:

drivers/gpu/drm/radeon/radeon_encoders.c

@@ -1999,6 +1999,53 @@ radeon_atom_dac_detect(struct drm_encoder *encoder, struct drm_connector *connec
 	return connector_status_disconnected;
 }
 
+static enum drm_connector_status
+radeon_atom_dig_detect(struct drm_encoder *encoder, struct drm_connector *connector)
+{
+	struct drm_device *dev = encoder->dev;
+	struct radeon_device *rdev = dev->dev_private;
+	struct radeon_encoder *radeon_encoder = to_radeon_encoder(encoder);
+	struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+	struct drm_encoder *ext_encoder = radeon_atom_get_external_encoder(encoder);
+	u32 bios_0_scratch;
+
+	if (!ASIC_IS_DCE4(rdev))
+		return connector_status_unknown;
+
+	if (!ext_encoder)
+		return connector_status_unknown;
+
+	if ((radeon_connector->devices & ATOM_DEVICE_CRT_SUPPORT) == 0)
+		return connector_status_unknown;
+
+	/* load detect on the dp bridge */
+	atombios_external_encoder_setup(encoder, ext_encoder,
+					EXTERNAL_ENCODER_ACTION_V3_DACLOAD_DETECTION);
+
+	bios_0_scratch = RREG32(R600_BIOS_0_SCRATCH);
+
+	DRM_DEBUG_KMS("Bios 0 scratch %x %08x\n", bios_0_scratch, radeon_encoder->devices);
+	if (radeon_connector->devices & ATOM_DEVICE_CRT1_SUPPORT) {
+		if (bios_0_scratch & ATOM_S0_CRT1_MASK)
+			return connector_status_connected;
+	}
+	if (radeon_connector->devices & ATOM_DEVICE_CRT2_SUPPORT) {
+		if (bios_0_scratch & ATOM_S0_CRT2_MASK)
+			return connector_status_connected;
+	}
+	if (radeon_connector->devices & ATOM_DEVICE_CV_SUPPORT) {
+		if (bios_0_scratch & (ATOM_S0_CV_MASK|ATOM_S0_CV_MASK_A))
+			return connector_status_connected;
+	}
+	if (radeon_connector->devices & ATOM_DEVICE_TV1_SUPPORT) {
+		if (bios_0_scratch & (ATOM_S0_TV1_COMPOSITE | ATOM_S0_TV1_COMPOSITE_A))
+			return connector_status_connected; /* CTV */
+		else if (bios_0_scratch & (ATOM_S0_TV1_SVIDEO | ATOM_S0_TV1_SVIDEO_A))
+			return connector_status_connected; /* STV */
+	}
+	return connector_status_disconnected;
+}
+
 static void radeon_atom_encoder_prepare(struct drm_encoder *encoder)
 {
 	struct radeon_encoder *radeon_encoder = to_radeon_encoder(encoder);
@@ -2162,7 +2209,7 @@ static const struct drm_encoder_helper_funcs radeon_atom_dig_helper_funcs = {
 	.mode_set = radeon_atom_encoder_mode_set,
 	.commit = radeon_atom_encoder_commit,
 	.disable = radeon_atom_encoder_disable,
-	/* no detect for TMDS/LVDS yet */
+	.detect = radeon_atom_dig_detect,
 };
 
 static const struct drm_encoder_helper_funcs radeon_atom_dac_helper_funcs = {