drm/i915: Implement ibx_digital_port_connected() for IBX

CPT+ PCHs have different bit definition to read the HPD live status. I
don't have an ILK with digital ports handy, which is why this patch is
separate from the CPT+ implementation. If the docs don't lie, it should
all be fine though.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -997,10 +997,21 @@ bool ibx_digital_port_connected(struct drm_i915_private *dev_priv,
 {
 	u32 bit;
 
-	/* XXX: IBX has different SDEISR bits */
-	if (HAS_PCH_IBX(dev_priv->dev))
+	if (HAS_PCH_IBX(dev_priv->dev)) {
+		switch(port->port) {
+		case PORT_B:
+			bit = SDE_PORTB_HOTPLUG;
+			break;
+		case PORT_C:
+			bit = SDE_PORTC_HOTPLUG;
+			break;
+		case PORT_D:
+			bit = SDE_PORTD_HOTPLUG;
+			break;
+		default:
 			return true;
-
+		}
+	} else {
 		switch(port->port) {
 		case PORT_B:
 			bit = SDE_PORTB_HOTPLUG_CPT;
@@ -1014,6 +1025,7 @@ bool ibx_digital_port_connected(struct drm_i915_private *dev_priv,
 		default:
 			return true;
 		}
+	}
 
 	return I915_READ(SDEISR) & bit;
 }