drm/i915: only enable hotplug for detected outputs

This patch changes around our hotplug enable code a bit to only enable
it for ports we actually detect and initialize.  This prevents problems
with stuck or spurious interrupts on outputs that aren't actually wired
up, and is generally more correct.

Fixes FDO bug #23183.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 85f4c5d..1733eea 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1084,6 +1084,10 @@
 	(void) I915_READ(IER);
 }
 
+/*
+ * Must be called after intel_modeset_init or hotplug interrupts won't be
+ * enabled correctly.
+ */
 int i915_driver_irq_postinstall(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
@@ -1106,19 +1110,23 @@
 	if (I915_HAS_HOTPLUG(dev)) {
 		u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
 
-		/* Leave other bits alone */
-		hotplug_en |= HOTPLUG_EN_MASK;
+		/* Note HDMI and DP share bits */
+		if (dev_priv->hotplug_supported_mask & HDMIB_HOTPLUG_INT_STATUS)
+			hotplug_en |= HDMIB_HOTPLUG_INT_EN;
+		if (dev_priv->hotplug_supported_mask & HDMIC_HOTPLUG_INT_STATUS)
+			hotplug_en |= HDMIC_HOTPLUG_INT_EN;
+		if (dev_priv->hotplug_supported_mask & HDMID_HOTPLUG_INT_STATUS)
+			hotplug_en |= HDMID_HOTPLUG_INT_EN;
+		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS)
+			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
+		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS)
+			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
+		if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS)
+			hotplug_en |= CRT_HOTPLUG_INT_EN;
+		/* Ignore TV since it's buggy */
+
 		I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
 
-		dev_priv->hotplug_supported_mask = CRT_HOTPLUG_INT_STATUS |
-			TV_HOTPLUG_INT_STATUS | SDVOC_HOTPLUG_INT_STATUS |
-			SDVOB_HOTPLUG_INT_STATUS;
-		if (IS_G4X(dev)) {
-			dev_priv->hotplug_supported_mask |=
-				HDMIB_HOTPLUG_INT_STATUS |
-				HDMIC_HOTPLUG_INT_STATUS |
-				HDMID_HOTPLUG_INT_STATUS;
-		}
 		/* Enable in IER... */
 		enable_mask |= I915_DISPLAY_PORT_INTERRUPT;
 		/* and unmask in IMR */