From bb78131d2d536752a695d9a20cc606a3a7141826 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 23 Sep 2010 11:16:49 +0100
Subject: [PATCH] --- yaml --- r: 218094 b: refs/heads/master c:
 428d2e828c0a68206e5158a42451487601dc9194 h: refs/heads/master v: v3

---
 [refs]                                  |  2 +-
 trunk/drivers/gpu/drm/i915/intel_lvds.c | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index fdfed85eee40..e42c8a674e9c 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 29e1316ab129f2d3a9ea874e7c9a4cb936f43542
+refs/heads/master: 428d2e828c0a68206e5158a42451487601dc9194
diff --git a/trunk/drivers/gpu/drm/i915/intel_lvds.c b/trunk/drivers/gpu/drm/i915/intel_lvds.c
index 2bcea8000859..e1f6e05169f6 100644
--- a/trunk/drivers/gpu/drm/i915/intel_lvds.c
+++ b/trunk/drivers/gpu/drm/i915/intel_lvds.c
@@ -810,6 +810,22 @@ static bool lvds_is_present_in_vbt(struct drm_device *dev)
 	return false;
 }
 
+static bool intel_lvds_ddc_probe(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u8 buf = 0;
+	struct i2c_msg msgs[] = {
+		{
+			.addr = 0xA0,
+			.flags = 0,
+			.len = 1,
+			.buf = &buf,
+		},
+	};
+	struct i2c_adapter *i2c = &dev_priv->gmbus[GMBUS_PORT_PANEL].adapter;
+	return i2c_transfer(i2c, msgs, 1) == 1;
+}
+
 /**
  * intel_lvds_init - setup LVDS connectors on this device
  * @dev: drm device
@@ -849,6 +865,11 @@ void intel_lvds_init(struct drm_device *dev)
 		gpio = PCH_GPIOC;
 	}
 
+	if (!intel_lvds_ddc_probe(dev)) {
+		DRM_DEBUG_KMS("LVDS did not respond to DDC probe\n");
+		return;
+	}
+
 	intel_lvds = kzalloc(sizeof(struct intel_lvds), GFP_KERNEL);
 	if (!intel_lvds) {
 		return;