drm/radeon/kms: improve bpc handling (v2)

Improve handling of bpc (bits per color) in radeon.
In most cases we want 8 except for HDMI, DP, LVDS, and eDP.

v2: handle DP better.

Signed-off-by: Alex Deucher <[e-mail]>
Tested-by: Lennert Buytenhek <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>

drivers/gpu/drm/radeon/atombios_crtc.c

···
 		if (encoder->crtc == crtc) {
 			radeon_encoder = to_radeon_encoder(encoder);
 			connector = radeon_get_connector_for_encoder(encoder);
-			/* if (connector && connector->display_info.bpc)
-				bpc = connector->display_info.bpc; */
+			bpc = radeon_get_monitor_bpc(connector);
 			encoder_mode = atombios_get_encoder_mode(encoder);
 			is_duallink = radeon_dig_monitor_is_duallink(encoder, mode->clock);
 			if ((radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT | ATOM_DEVICE_DFP_SUPPORT)) ||
···
 		struct radeon_connector_atom_dig *dig_connector =
 			radeon_connector->con_priv;
 		int dp_clock;
-
-		/* if (connector->display_info.bpc)
-			bpc = connector->display_info.bpc; */
+		bpc = radeon_get_monitor_bpc(connector);
 
 		switch (encoder_mode) {
 		case ATOM_ENCODER_MODE_DP_MST:

drivers/gpu/drm/radeon/atombios_dp.c

···
 /* get bpc from the EDID */
 static int convert_bpc_to_bpp(int bpc)
 {
-#if 0
 	if (bpc == 0)
 		return 24;
 	else
 		return bpc * 3;
-#endif
-	return 24;
 }
 
 /* get the max pix clock supported by the link rate and lane num */
···
 					u8 dpcd[DP_DPCD_SIZE],
 					int pix_clock)
 {
-	int bpp = convert_bpc_to_bpp(connector->display_info.bpc);
+	int bpp = convert_bpc_to_bpp(radeon_get_monitor_bpc(connector));
 	int max_link_rate = dp_get_max_link_rate(dpcd);
 	int max_lane_num = dp_get_max_lane_number(dpcd);
 	int lane_num;
···
 				       u8 dpcd[DP_DPCD_SIZE],
 				       int pix_clock)
 {
-	int bpp = convert_bpc_to_bpp(connector->display_info.bpc);
+	int bpp = convert_bpc_to_bpp(radeon_get_monitor_bpc(connector));
 	int lane_num, max_pix_clock;
 
 	if (radeon_connector_encoder_get_dp_bridge_encoder_id(connector) ==

drivers/gpu/drm/radeon/atombios_encoders.c

···
 		dp_clock = dig_connector->dp_clock;
 		dp_lane_count = dig_connector->dp_lane_count;
 		hpd_id = radeon_connector->hpd.hpd;
-		/* bpc = connector->display_info.bpc; */
+		bpc = radeon_get_monitor_bpc(connector);
 	}
 
 	/* no dig encoder assigned */
···
 		dp_lane_count = dig_connector->dp_lane_count;
 		connector_object_id =
 			(radeon_connector->connector_object_id & OBJECT_ID_MASK) >> OBJECT_ID_SHIFT;
-		/* bpc = connector->display_info.bpc; */
+		bpc = radeon_get_monitor_bpc(connector);
 	}
 
 	memset(&args, 0, sizeof(args));

drivers/gpu/drm/radeon/radeon_connectors.c

···
 					 crtc->x, crtc->y, crtc->fb);
 	}
 }
+
+int radeon_get_monitor_bpc(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	struct radeon_device *rdev = dev->dev_private;
+	struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+	struct radeon_connector_atom_dig *dig_connector;
+	int bpc = 8;
+
+	switch (connector->connector_type) {
+	case DRM_MODE_CONNECTOR_DVII:
+	case DRM_MODE_CONNECTOR_HDMIB:
+		if (radeon_connector->use_digital) {
+			if (drm_detect_hdmi_monitor(radeon_connector->edid)) {
+				if (connector->display_info.bpc)
+					bpc = connector->display_info.bpc;
+			}
+		}
+		break;
+	case DRM_MODE_CONNECTOR_DVID:
+	case DRM_MODE_CONNECTOR_HDMIA:
+		if (drm_detect_hdmi_monitor(radeon_connector->edid)) {
+			if (connector->display_info.bpc)
+				bpc = connector->display_info.bpc;
+		}
+		break;
+	case DRM_MODE_CONNECTOR_DisplayPort:
+		dig_connector = radeon_connector->con_priv;
+		if ((dig_connector->dp_sink_type == CONNECTOR_OBJECT_ID_DISPLAYPORT) ||
+		    (dig_connector->dp_sink_type == CONNECTOR_OBJECT_ID_eDP) ||
+		    drm_detect_hdmi_monitor(radeon_connector->edid)) {
+			if (connector->display_info.bpc)
+				bpc = connector->display_info.bpc;
+		}
+		break;
+	case DRM_MODE_CONNECTOR_eDP:
+	case DRM_MODE_CONNECTOR_LVDS:
+		if (connector->display_info.bpc)
+			bpc = connector->display_info.bpc;
+		else if (ASIC_IS_DCE41(rdev) || ASIC_IS_DCE5(rdev)) {
+			struct drm_connector_helper_funcs *connector_funcs =
+				connector->helper_private;
+			struct drm_encoder *encoder = connector_funcs->best_encoder(connector);
+			struct radeon_encoder *radeon_encoder = to_radeon_encoder(encoder);
+			struct radeon_encoder_atom_dig *dig = radeon_encoder->enc_priv;
+
+			if (dig->lcd_misc & ATOM_PANEL_MISC_V13_6BIT_PER_COLOR)
+				bpc = 6;
+			else if (dig->lcd_misc & ATOM_PANEL_MISC_V13_8BIT_PER_COLOR)
+				bpc = 8;
+		}
+		break;
+	}
+	return bpc;
+}
+
 static void
 radeon_connector_update_scratch_regs(struct drm_connector *connector, enum drm_connector_status status)
 {

drivers/gpu/drm/radeon/radeon_mode.h

···
 extern u16 radeon_connector_encoder_get_dp_bridge_encoder_id(struct drm_connector *connector);
 extern bool radeon_connector_encoder_is_hbr2(struct drm_connector *connector);
 extern bool radeon_connector_is_dp12_capable(struct drm_connector *connector);
+extern int radeon_get_monitor_bpc(struct drm_connector *connector);
 
 extern void radeon_connector_hotplug(struct drm_connector *connector);
 extern int radeon_dp_mode_valid_helper(struct drm_connector *connector,