drm/i915: Don't set up the TV port if it isn't in the BIOS table.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
index d7465ca27b97..9325dff21c06 100644
--- a/drivers/gpu/drm/i915/intel_tv.c
+++ b/drivers/gpu/drm/i915/intel_tv.c
@@ -1699,6 +1699,41 @@ static const struct drm_encoder_funcs intel_tv_enc_funcs = {
         .destroy = intel_tv_enc_destroy,
 };
 
+/*
+ * Enumerate the child dev array parsed from VBT to check whether
+ * the integrated TV is present.
+ * If it is present, return 1.
+ * If it is not present, return false.
+ * If no child dev is parsed from VBT, it assumes that the TV is present.
+ */
+int tv_is_present_in_vbt(struct drm_device *dev)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        struct child_device_config *p_child;
+        int i, ret;
+
+        if (!dev_priv->child_dev_num)
+                return 1;
+
+        ret = 0;
+        for (i = 0; i < dev_priv->child_dev_num; i++) {
+                p_child = dev_priv->child_dev + i;
+                /*
+                 * If the device type is not TV, continue.
+                 */
+                if (p_child->device_type != DEVICE_TYPE_INT_TV &&
+                        p_child->device_type != DEVICE_TYPE_TV)
+                        continue;
+                /* Only when the addin_offset is non-zero, it is regarded
+                 * as present.
+                 */
+                if (p_child->addin_offset) {
+                        ret = 1;
+                        break;
+                }
+        }
+        return ret;
+}
 
 void
 intel_tv_init(struct drm_device *dev)
@@ -1714,6 +1749,10 @@ intel_tv_init(struct drm_device *dev)
         if ((I915_READ(TV_CTL) & TV_FUSE_STATE_MASK) == TV_FUSE_STATE_DISABLED)
                 return;
 
+        if (!tv_is_present_in_vbt(dev)) {
+                DRM_DEBUG_KMS("Integrated TV is not present.\n");
+                return;
+        }
         /* Even if we have an encoder we may not have a connector */
         if (!dev_priv->int_tv_support)
                 return;