Use the DDC3 to see whether the EDID can be obtained.
---
 src/i830_sdvo.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: xf86_video_intel/src/i830_sdvo.c
===================================================================
--- xf86_video_intel.orig/src/i830_sdvo.c	2009-10-09 11:11:55.000000000 +0800
+++ xf86_video_intel/src/i830_sdvo.c	2009-10-09 11:44:54.000000000 +0800
@@ -2204,7 +2204,8 @@
     }
 
     /* Corresponds to SDVO_CONTROL_BUS_DDCx */
-    dev_priv->ddc_bus = 1 << num_bits;
+	/* use the DDC3 to see whether the edid can be obtained */
+    dev_priv->ddc_bus = 1 << 3;
 }
 /**
  * find the slave address for the given SDVO port based on the info