drm/i915: Skip SDVO/HDMI init when the chipset tells us it's not present.

This saves startup time from probing SDVO, and saves setting up HDMI outputs
on G4X devices that don't have them.

Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 31c3732..dce1abf 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1452,6 +1452,7 @@
 
 static void intel_setup_outputs(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_connector *connector;
 
 	intel_crt_init(dev);
@@ -1463,13 +1464,16 @@
 	if (IS_I9XX(dev)) {
 		int found;
 
-		found = intel_sdvo_init(dev, SDVOB);
-		if (!found && SUPPORTS_INTEGRATED_HDMI(dev))
-			intel_hdmi_init(dev, SDVOB);
-
-		found = intel_sdvo_init(dev, SDVOC);
-		if (!found && SUPPORTS_INTEGRATED_HDMI(dev))
-			intel_hdmi_init(dev, SDVOC);
+		if (I915_READ(SDVOB) & SDVO_DETECTED) {
+			found = intel_sdvo_init(dev, SDVOB);
+			if (!found && SUPPORTS_INTEGRATED_HDMI(dev))
+				intel_hdmi_init(dev, SDVOB);
+		}
+		if (!IS_G4X(dev) || (I915_READ(SDVOB) & SDVO_DETECTED)) {
+			found = intel_sdvo_init(dev, SDVOC);
+			if (!found && SUPPORTS_INTEGRATED_HDMI(dev))
+				intel_hdmi_init(dev, SDVOC);
+		}
 	} else
 		intel_dvo_init(dev);